To make it easier to debug things let's dump the output types bitmask in
the crtc state dump. And to make life that much better, let's pretty
print it as a a human reaadable string as well.

v2: Have the caller pass in the buffer (Chris)
    #undef OUTPUT_TYPE (Jani)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010121207.570-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>