radv: handle fragment shader srgb resolve pass better

radv: handle fragment shader srgb resolve pass better

Bas pointed out the fs key doesn't take srgb into account,
since there is just one srgb variant, just create a separate
pipeline for it. This also uses dest format to be more consistent
on when srgb matters.

Fixes: 69136f4e633 "radv/meta: add resolve pass using fragment/vertex shaders"
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>