drm/i915: Dump blanking start/end

drm/i915: Dump blanking start/end

With the delayed vblank we need to start knowing where
the blanking periods start. So let's start dumping
out also the blanking start/end timings.

And while at it let's try to make that huge list of
numbers somewhat legible by indicating what each value
means. Also drop the 'type' since that doesn't really
mean anything for the crtc_ timings.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230213225258.2127-6-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>