drm/i915/mtl/huc: auth HuC via GSC

The full authentication via the GSC requires an heci packet submission
to the GSC FW via the GSC CS. The GSC has new PXP command for this
(literally called NEW_HUC_AUTH).
The intel_huc_auth function is also updated to handle both authentication
types.

v2: check that the GuC auth for clear media has completed before
    proceding with the full auth

v3: use a define for the object size (Alan)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230531235415.1467475-6-daniele.ceraolospurio@intel.com