V4L/DVB (12175): davinci/vpif: Add Video Port Interface (VPIF) driver

This code be used by the display and capture drivers.

Signed-off-by: Manjunath Hadli <mrh@ti.com>
Signed-off-by: Brijesh Jadav <brijesh.j@ti.com>
Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>