DaVinci: DM646x - platform changes for vpif capture and display drivers

VPIF display changes (Chaithrika)

Add platform device and resource structures. Also define a platform specific
clock setup function that can be accessed by the driver to configure the clock
and CPLD.

VPIF caputure changes (Murali)

1) Modify vpif_subdev_info to add board_info, routing information and
   vpif interface configuration. Remove addr since it is part of
   board_info

2) Add code to setup channel mode and input decoder path for vpif
   capture driver

Also incorporated comments against version v0 of the patch series and
added a spinlock to protect writes to common registers

Tested on DM6467 on channel 0 using TVP514x. Following bootargs used
for drivers:

   vpif_capture.ch0_bufsize=829440 vpif_display.ch2_bufsize=829440

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>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Muralidharan Karicheri <m-karicheri2@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>