arm64: dts: freescale: imx8-ss-lsio: add support for lsio_pwm0-3

Add support for lsio_pwm0-3.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>