drm/i915/guc: support v69 in parallel to v70

drm/i915/guc: support v69 in parallel to v70

This patch re-introduces support for GuC v69 in parallel to v70. As this
is a quick fix, v69 has been re-introduced as the single "fallback" guc
version in case v70 is not available on disk and only for platforms that
are out of force_probe and require the GuC by default. All v69 specific
code has been labeled as such for easy identification, and the same was
done for all v70 functions for which there is a separate v69 version,
to avoid accidentally calling the wrong version via the unlabeled name.

When the fallback mode kicks in, a drm_notice message is printed in
dmesg to inform the user of the required update. The existing
logging of the fetch function has also been updated so that we no
longer complain immediately if we can't find a fw and we only throw an
error if the fetch of both the base and fallback blobs fails.

The plan is to follow this up with a more complex rework to allow for
multiple different GuC versions to be supported at the same time.

v2: reduce the fallback to platform that require it, switch to
firmware_request_nowarn(), improve logs.

Fixes: 2584b3549f4c ("drm/i915/guc: Update to GuC version 70.1.1")
Link: https://lists.freedesktop.org/archives/intel-gfx/2022-July/301640.html
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718230732.1409641-1-daniele.ceraolospurio@intel.com