r600g: remove unsupported evergreen CB formats
r600g: remove unsupported evergreen CB formats

The evergreen+ CB no longer supports the following formats
compared to 6xx/7xx:
- COLOR_4_4
- COLOR_3_3_2
- COLOR_6_5_5
- COLOR_8_24_FLOAT
- COLOR_24_8_FLOAT
- COLOR_11_11_10
- COLOR_11_11_10_FLOAT

Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>

bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,metora/MesaGLSLCompiler,mapbox/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,metora/MesaGLSLCompiler,wolf96/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,jbarczak/glsl-optimizer,mcanthony/glsl-optimizer,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,mcanthony/glsl-optimizer,wolf96/glsl-optimizer,jbarczak/glsl-optimizer,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,metora/MesaGLSLCompiler,zeux/glsl-optimizer,benaadams/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,dellis1972/glsl-optimizer