ARM: dts: davinci: da850-evm: enable VPIF

Enable VPIF node for video capture, and configure ports.  EVM board
uses channel 0 for composite input and channel 1 S-Video input.

Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>