i965: Enable regular fast-clears (CCS_D) on gen9+
The set of formats which supports CCS_E is actually fairly small on
gen9. However, everything that supports fast-clears on gen8 also
supports fast-clears on gen9+. The one very annoying exception is
that blending is broken for non-0/1 clear colors with sRGB formats.
In order to solve that problem, we do a resolve to get rid of the
clear color. Another option would be to just not fast-clear with
non-0/1 clear colors however non-0/1 + blending + sRGB is uncommon
enough that this shouldn't be a significant performance problem.
This appears to help gl_manhattan31_off by about 2%.
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>