r600g,radeonsi: move CMASK register values from r600_surface to r600_texture

r600g,radeonsi: move CMASK register values from r600_surface to r600_texture

When doing fast clear for single-sample color buffers for the first time,
a CMASK buffer has to be allocated and the CMASK state in all pipe_surfaces
referencing the color buffer must be updated. Updating all surfaces is kinda
silly, so let's move the values to r600_texture instead.

This is only for Evergreen and later. R600-R700 don't have fast clear.

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>