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: 588185eb "radv/meta: add srgb conversion to end of resolve shader." Reviewed-by:Dave Airlie <airlied@redhat.com> (cherry picked from commit 8286c3a4)