video: mmp display controller support

Marvell mmp series display controller support in mmpdisp subsystem.

This driver focus on implementation of hardware operations of
path/overlay, which is defined in mmp display subsystem interface.  This
driver registers all pathes to mmp display framework.

Signed-off-by: Guoqing Li <ligq@marvell.com>
Signed-off-by: Lisa Du <cldu@marvell.com>
Signed-off-by: Zhou Zhu <zzhu3@marvell.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>