drm/i915/dp: Detect changes in common link parameters

drm/i915/dp: Detect changes in common link parameters

Detect DPRX capability changes without a long HPD or RX_CAP_CHANGED
signal and queue a corresponding link params reset.

Besides detecting the above unexpected capability changes, this also
avoids races between queuing and handling a deferred link params reset.

v2: (Ville)
- Query/set intel_dp::reset_link_params instead of using helpers for
  these.
- Assert matching types for old/new common rate elements as well.
- Add TODO: for adding a struct tracking both rates and number of rates.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260522160514.2628249-5-imre.deak@intel.com