ARM: dts: imx: Synchronize iMX6QDL DHCOM PDK2 DTs with Linux 5.15.12

Synchronize DH DHCOM DTs with Linux commit 25960cafa06e ("Linux 5.15.12").
There is no functional change to the resulting DTs. The imx6qdl-dhcom-pdk2.dtsi
had to be adjusted with additional headers, gpio.h, pwm.h, input.h, else
the DT cannot be compiled, the same change is likely necessary in Linux.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/arch/arm/dts/imx6q-dhcom-pdk2.dts b/arch/arm/dts/imx6q-dhcom-pdk2.dts
index 5bab2db..d4d5737 100644
--- a/arch/arm/dts/imx6q-dhcom-pdk2.dts
+++ b/arch/arm/dts/imx6q-dhcom-pdk2.dts
@@ -1,20 +1,25 @@
-// SPDX-License-Identifier: (GPL-2.0+)
+// SPDX-License-Identifier: GPL-2.0+
 /*
- * Copyright (C) 2015-2019 DH electronics GmbH
+ * Copyright (C) 2015-2021 DH electronics GmbH
  * Copyright (C) 2018 Marek Vasut <marex@denx.de>
+ *
+ * DHCOM iMX6 variant:
+ * DHCM-iMX6Q-C0800-R102-F0819-E-SD-RTC-T-HS-I-01D2
+ * DHCOM PCB number: 493-300 or newer
+ * PDK2 PCB number: 516-400 or newer
  */
-
 /dts-v1/;
 
 #include "imx6q.dtsi"
+#include "imx6qdl-dhcom-som.dtsi"
 #include "imx6qdl-dhcom-pdk2.dtsi"
 
 / {
-	model = "Freescale i.MX6 Quad/Dual DHCOM Premium Developer Kit (2)";
-	compatible = "dh,imx6q-dhcom-pdk2", "dh,imx6q-dhcom", "fsl,imx6q";
+	model = "DH electronics i.MX6Q DHCOM on Premium Developer Kit (2)";
+	compatible = "dh,imx6q-dhcom-pdk2", "dh,imx6q-dhcom-som",
+		     "fsl,imx6q";
 };
 
 &sata {
 	status = "okay";
 };
-