meta-inspur: Cleanup for Yocto override syntax change

Refer to: https://lore.kernel.org/openbmc/YQ1FD5q8KbhbXVBK@heinlein/

```
poky/scripts/contrib/convert-overrides.py meta-inspur

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

git grep -l _fp5280g2 -- meta-inspur | xargs sed -i \
's/_fp5280g2/:fp5280g2/'
git grep -l _on5263m5 -- meta-inspur | xargs sed -i \
's/_on5263m5/:on5263m5/'
git grep -l _virtual  -- meta-inspur | xargs sed -i \
's/_virtual/:virtual/'

```

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I5ef5039691caf5e33fb865da0fdd70d95d7e3bdf
diff --git a/meta-inspur/meta-on5263m5/conf/local.conf.sample b/meta-inspur/meta-on5263m5/conf/local.conf.sample
index 5defaa1..59f0046 100644
--- a/meta-inspur/meta-on5263m5/conf/local.conf.sample
+++ b/meta-inspur/meta-on5263m5/conf/local.conf.sample
@@ -114,7 +114,7 @@
 # running the build on (i.e. building i686 packages on an x86_64 host).
 # Supported values are i686 and x86_64
 #SDKMACHINE ?= "i686"
-SANITY_TESTED_DISTROS_append ?= " RedHatEnterpriseWorkstation-6.*"
+SANITY_TESTED_DISTROS:append ?= " RedHatEnterpriseWorkstation-6.*"
 
 #
 # Extra image configuration defaults
@@ -138,7 +138,7 @@
 # There are other application targets that can be used here too, see
 # meta/classes/image.bbclass and meta/classes/core-image.bbclass for more details.
 # We default to enabling the debugging tweaks.
-EXTRA_IMAGE_FEATURES = "debug-tweaks"
+EXTRA_IMAGE_FEATURES ?= "debug-tweaks"
 
 #
 # Additional image features
@@ -190,7 +190,7 @@
 # files and damages the build in ways which may not be easily recoverable.
 # It's necessary to monitor /tmp, if there is no space left the build will fail
 # with very exotic errors.
-BB_DISKMON_DIRS = "\
+BB_DISKMON_DIRS ??= "\
     STOPTASKS,${TMPDIR},1G,100K \
     STOPTASKS,${DL_DIR},1G,100K \
     STOPTASKS,${SSTATE_DIR},1G,100K \
@@ -224,8 +224,8 @@
 # By default qemu will build with a builtin VNC server where graphical output can be
 # seen. The two lines below enable the SDL backend too. This assumes there is a
 # libsdl library available on your build system.
-PACKAGECONFIG_append_pn-qemu-native = " sdl"
-PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"
+PACKAGECONFIG:append:pn-qemu-native = " sdl"
+PACKAGECONFIG:append:pn-nativesdk-qemu = " sdl"
 #ASSUME_PROVIDED += "libsdl-native"
 
 # CONF_VERSION is increased each time build/conf/ changes incompatibly and is used to