arm64: dts: ti: k3-am642: reserve gpio in mcu domain for firmware usage

The gpio0 subsystem present in MCU domain might be used by firmware and is
not pinned out in evm/sk. Therefore, reserve it for MCU firmware.
Signed-off-by: NAswath Govindraju <a-govindraju@ti.com>
Signed-off-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NLokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210319051950.17549-3-a-govindraju@ti.com

arch/arm64/boot/dts/ti/k3-am642-evm.dts

@@ -310,6 +310,11 @@
 	};
 };
 
+/* mcu_gpio0 is reserved for mcu firmware usage */
+&mcu_gpio0 {
+	status = "reserved";
+};
+
 &mcu_i2c0 {
 	status = "disabled";
 };

arch/arm64/boot/dts/ti/k3-am642-sk.dts

@@ -220,6 +220,11 @@
 	status = "disabled";
 };
 
+/* mcu_gpio0 is reserved for mcu firmware usage */
+&mcu_gpio0 {
+	status = "reserved";
+};
+
 &sdhci1 {
 	/* SD/MMC */
 	vmmc-supply = <&vdd_mmc1>;