drm/i915/hpd: Replace the loop-within-loop with two independent loops

No point in looping over all connectors for each hpd pin. Just loop
over each connector first and deal with each one's hpd pin. Then
loop over all the hpd pins to mark them as enabled again.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200205183546.9291-2-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>