ARM: dts: am437x-sk-evm: add VPFE device tree data

Add device tree nodes and pinmux entries for Video Processing
Front End (VPFE) on am437x sk evm.

Signed-off-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>