drm/i915: Refactor debugfs display info code

Pull the crtc dumping stuff into a nice function so the
loop over the crtcs doesn't look like crap.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129185434.25549-5-ville.syrjala@linux.intel.com


Reviewed-by: Ramalingam C <ramalingam.c@intel.com>