conf: drop gatesgarth from compatibility
conf: drop gatesgarth from compatibility

There have been reports of warnings being generated by the
layer index when the compatibility of a layer exceeds 25 characters.

gatesgarth is supported in its own branch, and isn't being tested
against master, so we drop it from the compat.

Signed-off-by: Bruce Ashfield <284cc737d174a260eec2a2a6324a304f84b1ae0f@gmail.com>

lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization