spirv: Only require bare types to match when copying variables
OpCopyMemory doesn't care about mismatched decorations, only about matching types. Closes: mesa/mesa#3418 Fixes: bf1a1eed Signed-off-by:Danylo Piliaiev <danylo.piliaiev@globallogic.com> Reviewed-by:
Jason Ekstrand <jason@jlekstrand.net> Part-of: <mesa/mesa!6344>