drm/i915/dp: Use check link state work in the hotplug handler

drm/i915/dp: Use check link state work in the hotplug handler

Simplify things by retraining a DP link if a bad link is detected in the
hotplug handler from the encoder's check link state work, similarly to
how this is done after a modeset link training failure.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240610164933.2947366-12-imre.deak@intel.com