drm/i915: Kill unused savePCH_PORT_HOTPLUG

We don't save/restore PCH_PORT_HOTPLUG so no point in reseving
space for the value.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200908140210.31048-1-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>