drm/i915/mtl: Skip MCR ops for ring fault register

On MTL GEN12_RING_FAULT_REG is not replicated so don't
do mcr based operation for this register.

v2: use MEDIA_VER() instead of GRAPHICS_VER()(Matt).
v3: s/"MEDIA_VER(i915) == 13"/"MEDIA_VER(i915) >= 13"(Matt)
    improve comment.
v4: improve the comment further(Andi)

Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230928130015.6758-4-nirmoy.das@intel.com