[media] marvell-cam: Basic working MMP camera driver

Now we have a camera working over the marvell cam controller core.  It
works like the cafe driver and has all the same limitations, contiguous DMA
only being one of them.  But it's a start.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>