drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address

drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address

Commit bd077259d0a9 ("drm/i915/vdsc: Add function to read any PPS
register") defines a new macro to calculate the DSC PPS register
addresses with PPS number as an input. This macro correctly calculates
the addresses till PPS 11 since the addresses increment by 4. So in that
case the following macro works correctly to give correct register
address:

_MMIO(_DSCA_PPS_0 + (pps) * 4)

However after PPS 11, the register address for PPS 12 increments by 12
because of RC Buffer memory allocation in between. Because of this
discontinuity in the address space, the macro calculates wrong addresses
for PPS 12 - 16 resulting into incorrect DSC PPS parameter value
read/writes causing DSC corruption.

This fixes it by correcting this macro to add the offset of 12 for PPS
>=12.

v3: Add correct paranthesis for pps argument (Jani Nikula)

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10172
Fixes: bd077259d0a9 ("drm/i915/vdsc: Add function to read any PPS register")
Cc: Suraj Kandpal <suraj.kandpal@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Drew Davenport <ddavenport@chromium.org>
Signed-off-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240205204619.1991673-1-navaremanasi@chromium.org