[media] mt9p031: Aptina (Micron) MT9P031 5MP sensor driver

The MT9P031 is a parallel 12-bit 5MP sensor from Aptina (formerly
Micron) controlled through I2C.

The driver creates a V4L2 subdevice. It currently supports skipping,
cropping, automatic binning, and gain, exposure, h/v flip and test
pattern controls.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>