HACK/i965/surface_formats: Mark A4B4G4R4 as being supported
HACK/i965/surface_formats: Mark A4B4G4R4 as being supported

The table has this marked as unsupported on all gens, but I don't really
believe that given how early it is in the table.  I've tested and it seems
to work on Broadwell.  The Bspec says that it sould be renderable on SKL+
but alpha blending is questionable.

Side note: We really need to audit the format table again.

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler