drm/i915/guc: Update 'recommended' version to 70.12.1 for DG2/ADL-S/ADL-P/MTL

The latest GuC has new features and new workarounds that we wish to
enable. So let the universe know that it is useful to update their
firmware.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231006145801.161868-1-John.C.Harrison@Intel.com