ARM: dts: imx: ventana: add PWM nodes for Ventana boards

Ventana boards have an off-board connector with signals that can be pinmuxed
as either GPIO or PWM. This patch adds pwm device-tree nodes in the disabled
state which the bootloader can decide to enable based on bootloader config.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>