drm/dp: Add Panel Replay capability bits from DP2.1 specification

Add PANEL REPLAY CAPABILITY register (0xb1) bits.

v3:
  - added DP_DSC_DECODE_CAPABILITY definitions
  - use defined shift instead of hardcoded value
v2: comment about DP2.1 changed as DP2.1a

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://lore.kernel.org/r/20250526120512.1702815-3-jouni.hogander@intel.com