drm/i915/mtl: Handle wopcm per-GT and limit calculations.

With MTL standalone media architecture the wopcm layout has changed,
with separate partitioning in WOPCM for the root GT GuC and the media
GT GuC. The size of WOPCM is 4MB with the lower 2MB reserved for the
media GT and the upper 2MB for the root GT.

Given that MTL has GuC deprivilege, the WOPCM registers are pre-locked
by the bios. Therefore, we can skip all the math for the partitioning
and just limit ourselves to sanity-checking the values.

v2: fix makefile file ordering (Jani)
v3: drop XELPM_SAMEDIA_WOPCM_SIZE, check huc instead of VDBOX (John)
v4: further clarify commit message, remove blank line (John)

Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: John Harrison <john.c.harrison@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221108020600.3575467-5-daniele.ceraolospurio@intel.com