fbdev: add a MIPI DSI header

This header adds defines for MIPI DSI and DCS commands and data formats. See
http://www.mipi.org/

 for details.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>