drm/i915: Print the long_mask alongside the pin_mask

We're printing out which pins got a hotplug, so why not also print
out which pins detected the long pulse as opposed to a short pulse.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180705164357.28512-9-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>