video: fbdev/mmp: add MODULE_LICENSE

Kbuild complains about the lack of a license tag in this driver:

WARNING: modpost: missing MODULE_LICENSE() in drivers/video/fbdev/mmp/mmp_disp.o

This adds the license, author and description tags.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>