ARM: dts: imx7-colibri: make sure multiplexed pins are not active

The Colibri pins PWM<A> and <D> are multiplexed on the module, make
sure the secondary SoC pin is not active.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>