tree 80cb87a34afb07b7d375b534bb5df68468c2b5a6
parent d97cf9b9ef84cdad2f357164e36b76619e7dc379
author Patrick Williams <patrick@stwcx.xyz> 1630531053 -0500
committer Patrick Williams <patrick@stwcx.xyz> 1630588765 +0000

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