drm/i915: Move the g45 PEG band gap HPD workaround to the HPD code

drm/i915: Move the g45 PEG band gap HPD workaround to the HPD code

We are asked to reprogram PEG_BAND_GAP_DATA prior to enabling
hotplug detection on the g45 HDMI/DP ports. Currently we do said
reprogamming from the DP/HDMI connector initialization functions.
That code should be mostly platform agnostic so clearly not the
best place for this. Move the workaround to the place where we
actually enable HPD detection.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231012124033.26983-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>