meta-phosphor: change systemd.bbclass to match upstream override syntax

Upstream bbclasses changed to typically use the `:${PN}` override
syntax, including the SYSTEMD_ variables.  Change our systemd.bbclass
to do the same for consistency and perform a tree-wide variable
replacement.

Spot checked by building bletchley and witherspoon and checking
some of the SYSTEMD_LINK directives on installed packages under qemu.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I20a9dd809bff8af8759488734f80486c7228c6eb
diff --git a/meta-openpower/classes/openpower-software-manager-virtual-pnor.bbclass b/meta-openpower/classes/openpower-software-manager-virtual-pnor.bbclass
index 61822f1..d37ebc3 100644
--- a/meta-openpower/classes/openpower-software-manager-virtual-pnor.bbclass
+++ b/meta-openpower/classes/openpower-software-manager-virtual-pnor.bbclass
@@ -26,8 +26,8 @@
 CHECK_CLEAR_VOLATILE_INSTFMT = "obmc-vpnor-check-clearvolatile@{0}.service"
 CHECK_CLEAR_VOLATILE_START_FMT = "../${CHECK_CLEAR_VOLATILE_TMPL}:${HOST_STARTMIN_TGTFMT}.requires/${CHECK_CLEAR_VOLATILE_INSTFMT}"
 
-SYSTEMD_LINK_${PN} += "${@compose_list_zip(d, 'ENABLE_CLEAR_VOLATILE_START_FMT', 'OBMC_HOST_INSTANCES')}"
-SYSTEMD_LINK_${PN} += "${@compose_list_zip(d, 'CHECK_CLEAR_VOLATILE_START_FMT', 'OBMC_HOST_INSTANCES')}"
+SYSTEMD_LINK:${PN} += "${@compose_list_zip(d, 'ENABLE_CLEAR_VOLATILE_START_FMT', 'OBMC_HOST_INSTANCES')}"
+SYSTEMD_LINK:${PN} += "${@compose_list_zip(d, 'CHECK_CLEAR_VOLATILE_START_FMT', 'OBMC_HOST_INSTANCES')}"
 
 # Chassis target installation - always enable and clear in chassis
 # power on
@@ -36,5 +36,5 @@
 
 CHECK_CLEAR_VOLATILE_PON_FMT = "../${CHECK_CLEAR_VOLATILE_TMPL}:${CHASSIS_PON_TGTFMT}.requires/${CHECK_CLEAR_VOLATILE_INSTFMT}"
 
-SYSTEMD_LINK_${PN} += "${@compose_list_zip(d, 'ENABLE_CLEAR_VOLATILE_PON_FMT', 'OBMC_CHASSIS_INSTANCES')}"
-SYSTEMD_LINK_${PN} += "${@compose_list_zip(d, 'CHECK_CLEAR_VOLATILE_PON_FMT', 'OBMC_CHASSIS_INSTANCES')}"
+SYSTEMD_LINK:${PN} += "${@compose_list_zip(d, 'ENABLE_CLEAR_VOLATILE_PON_FMT', 'OBMC_CHASSIS_INSTANCES')}"
+SYSTEMD_LINK:${PN} += "${@compose_list_zip(d, 'CHECK_CLEAR_VOLATILE_PON_FMT', 'OBMC_CHASSIS_INSTANCES')}"