V4L/DVB: v4l: Add MPC5121e VIU video capture driver

Adds support for Video-In (VIU) unit of Freescale
MPC5121e. The driver supports RGB888/RGB565 formats,
capture and overlay on MPC5121e DIU frame buffer.

Signed-off-by: Hongjun Chen <hong-jun.chen@freescale.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>