ARM: dts: add Plymovent M2M board

Plymovent M2M is a control interface produced for the Plymovent filter
systems.
Co-Developed-by: David Jander <david@protonic.nl>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/Makefile

@@ -465,6 +465,7 @@ dtb-$(CONFIG_SOC_IMX6Q) += \
 	imx6dl-pico-hobbit.dtb \
 	imx6dl-pico-nymph.dtb \
 	imx6dl-pico-pi.dtb \
+	imx6dl-plym2m.dtb \
 	imx6dl-prtrvt.dtb \
 	imx6dl-prtvt7.dtb \
 	imx6dl-rex-basic.dtb \