radv: Don't use SRGB format for image stores during resolve.

radv: Don't use SRGB format for image stores during resolve.

These seem to store very bogus results. Luckily there is some code
that converts srgb->linear already, so just making the descriptor
format UNORM should work.

Fixes: 588185eb6b7 "radv/meta: add srgb conversion to end of resolve shader."
Reviewed-by: Dave Airlie <airlied@redhat.com>