video: add fb_edid_add_monspecs for parsing extended edid information

Modern monitors/tvs have more extended EDID information blocks which can
contain extra detailed modes.  This adds a fb_edid_add_monspecs function
which drivers can use to parse those additions blocks.

Signed-off-by: Erik Gilling <konkers@android.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>