radv: Only convert linear->srgb in compute resolves.

radv: Only convert linear->srgb in compute resolves.

It justs works with the fragment shader resolve, so no need to do
a custom conversion. In fact with SRGB dest, it actually gives
wrong results.

Fixes: 69136f4e633 "radv/meta: add resolve pass using fragment/vertex shaders"
Reviewed-by: Dave Airlie <airlied@redhat.com>