ARM: dts: vf610: Add Freescale FTM PWM node.

This adds devicetree node for VF610, and there are 8 channels
supported.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>