gallium/radeon: discard CMASK or DCC if overwriting a whole texture by DMA
gallium/radeon: discard CMASK or DCC if overwriting a whole texture by DMA

v2: simplify the conditionals

Reviewed-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com> (v1)
Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler