video: mmp fb support

Add fb support for Marvell mmp display subsystem.  This driver is
configured using "buffer driver mach info".  With configured name of path,
this driver get path using using exported interface of mmp display driver.
Then this driver get overlay using configured id and operates on this
overlay to show buffers on display devices.

Signed-off-by: Zhou Zhu <zzhu3@marvell.com>
Signed-off-by: Lisa Du <cldu@marvell.com>
Cc: Guoqing Li <ligq@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>