This will let us pass kms_hdr.bpc_switch.

I don't see any good reasons why we still need to
limit bpc to 8 bpc and doing so is problematic when
we enable HDR.

If I remember correctly there might have been some
displays out there where the advertised link bandwidth
was not large enough to drive the default timing at
max bpc. This would leave to an atomic commit/check
failure which should really be handled in compositors
with some sort of fallback mechanism.

If this somehow turns out to still be an issue I
suggest we add a module parameter to allow users to
limit the max_bpc to a desired value.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org