meta-google: Cleanup for Yocto override syntax change

```
convert-overrides.py meta-google

git grep "_[a-z0-9_/-]*[ :]" -- meta-google | grep ".bb"

git grep -l _gbmc -- meta-google | grep ".bb" \
  | xargs sed -i 's/_gbmc/:gbmc/'
git grep -l _prod -- meta-google | grep ".bb" \
  | xargs sed -i 's/_prod/:prod/'
git grep -l _dev -- meta-google | grep ".bb" \
  | xargs sed -i 's/_dev/:dev/'
git grep -l _hoth -- meta-google | grep ".bb" \
  | xargs sed -i 's/_hoth/:hoth/'
git grep -l _bandaid -- meta-google | grep ".bb" \
  | xargs sed -i 's/_bandaid/:bandaid/'
```

Some small fix includes
```
platforms_gbmc_bringup
platforms_gbmc_secure
```

Tested:
```
$  git grep "_[a-z0-9_/-]*[ :]" -- meta-google | grep ".bb"
meta-google/recipes-connectivity/avahi/avahi_%.bbappend:do_install:append:gbmc() {
meta-google/recipes-core/dropbear/dropbear_%.bbappend:do_install:append:gbmc:dev() {
meta-google/recipes-core/dropbear/dropbear_%.bbappend:  echo '    chain gbmc_br_pub_input {' >>"$rules"
meta-google/recipes-extended/libconfig/conf2struct-native_git.bb:    oe_runmake checker
meta-google/recipes-extended/libconfig/conf2struct-native_git.bb:    oe_runmake install
meta-google/recipes-extended/networking/mstpd_git.bb:do_install:append() {
meta-google/recipes-extended/networking/sslh_git.bb:  oe_runmake distclean
meta-google/recipes-extended/networking/sslh_git.bb:  oe_runmake sslh-conf.h
meta-google/recipes-extended/networking/sslh_git.bb:  oe_runmake install
meta-google/recipes-google/ipmi/ipmi-fru-sh.bb:do_install:append() {
meta-google/recipes-google/ncsi/gbmc-ncsi-config.bb:do_install:append() {
meta-google/recipes-google/networking/gbmc-bridge.bb:do_rm_work:prepend() {
meta-google/recipes-google/networking/gbmc-bridge.bb:  # HACK: Work around broken do_rm_work not properly calling rm with `--`
meta-google/recipes-google/networking/gbmc-ip-monitor.bb:do_install:append() {
meta-google/recipes-google/networking/gbmc-iperf3.bb:do_install:append:dev() {
meta-google/recipes-google/networking/gbmc-iperf3.bb:  echo '    chain gbmc_br_pub_input {' >>"$rules"
meta-google/recipes-google/networking/gbmc-mac-config.bb:do_install:append() {
meta-google/recipes-google/networking/network-sh.bb:do_install:append() {
meta-google/recipes-google/ssh/authorized-keys-comp.bb:SUMMARY = "Compiles a set of authorized_keys files into a single file"
meta-google/recipes-google/ssh/authorized-keys-comp.bb:do_install:append() {
meta-google/recipes-google/systemd/gbmc-systemd-config.bb:do_install:append:dev() {
meta-google/recipes-google/test/test-sh.bb:do_install:append() {
meta-google/recipes-phosphor/flash/inplace-gbmc-update.bb:do_install:prepend:dev() {
meta-google/recipes-phosphor/host/phosphor-host-postd_%.bbappend:do_install:append:gbmc:dev() {
meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend:do_install:append:gbmc:dev() {
meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend:do_install:append:gbmc:prod() {
meta-google/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend:do_install:append:gbmc() {
meta-google/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend:  overlapping="$(jq '."${GBMCBR_IPMI_CHANNEL}" | .is_valid and .name != "gbmcbr"' $chjson)"
```

Change-Id: I9d610c664bd44e8bd81fb8f7e76249a0b43b9ffd
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend b/meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend
index 905a39a..de696ef 100644
--- a/meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend
+++ b/meta-google/recipes-phosphor/initrdscripts/obmc-phosphor-initfs.bbappend
@@ -1,20 +1,20 @@
 # This is needed to guarantee that our whitelist takes
 # precendence over the OpenBMC one
-FILESEXTRAPATHS_prepend_gbmc := "${THISDIR}/${PN}:"
+FILESEXTRAPATHS:prepend:gbmc := "${THISDIR}/${PN}:"
 
-SRC_URI_append_gbmc_dev = " file://whitelist.dev"
+SRC_URI:append:gbmc:dev = " file://whitelist.dev"
 
-do_install_append_gbmc_dev() {
+do_install:append:gbmc:dev() {
     cat ${WORKDIR}/whitelist.dev >>${D}/whitelist
 }
 
-SRC_URI_append_gbmc_dev = " file://rwfs-clean-dev.patch"
+SRC_URI:append:gbmc:dev = " file://rwfs-clean-dev.patch"
 # Required for the clean-dev patch to detect version changes
-RDEPENDS_${PN}_append_gbmc_dev = " os-release"
+RDEPENDS:${PN}:append:gbmc:dev = " os-release"
 
-do_install_append_gbmc_prod() {
+do_install:append:gbmc:prod() {
     echo "clean-rwfs-filesystem" > ${D}/init-options-base
     chmod 0644 ${D}/init-options-base
 }
 
-FILES_${PN}_append_gbmc_prod = " /init-options-base"
+FILES:${PN}:append:gbmc:prod = " /init-options-base"