drm/i915/psr: Use SU granularity information available in intel_connector

drm/i915/psr: Use SU granularity information available in intel_connector

Currently we are storing only one set of granularity information for panels
supporting both PSR and Panel Replay. As panel is informing own
granularities for PSR and Panel Replay they could be different. Let's use
own granularities for PSR and Panel Replay instead of having only one set
for both. This is done by having intel_connector::psr_caps and
panel_replay_caps both containing granularity information.

Also remove complexity of sharing granularity read between PSR and Panel
Replay.

v3:
  - use cpu_to_le16 for default value
v2:
  - use __le16 for two byte values in dpcd
  - use sizeof instead of hardcoded size in reading dpcd
  - drop unnecessarily passing intel_dp pointer

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20251204104733.1106145-3-jouni.hogander@intel.com