panfrost: Merge emit_texture_payload() and emit_texture_payload_v7()

panfrost: Merge emit_texture_payload() and emit_texture_payload_v7()

The only reason we have two different functions to prepare the texture
payload is the different ordering between pre-v7 and v7+ GPUs. Abstract
the surface iteration so we can merge panfrost_emit_texture_payload_v7()
and panfrost_emit_texture_payload().

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8125>