drm/i915/dp: Align min/max compressed BPPs when calculating BPP limits

drm/i915/dp: Align min/max compressed BPPs when calculating BPP limits

Align the minimum/maximum DSC compressed BPPs to the corresponding
source compressed BPP limits already when computing the BPP limits. This
alignment is also performed later during state computation, however
there is no reason to initialize the limits to an unaligned/incorrect
value.

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20251222153547.713360-7-imre.deak@intel.com