arm64: dts: msm8996: add msmgpio label

This patch adds msmgpio label for pin and gpio controller so that
it can referenced in dedicated pins file and other board level gpios.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

arch/arm64/boot/dts/qcom/msm8996.dtsi

@@ -161,7 +161,7 @@ blsp2_uart1: serial@75b0000 {
 			status = "disabled";
 		};
 
-		pinctrl@1010000 {
+		msmgpio: pinctrl@1010000 {
 			compatible = "qcom,msm8996-pinctrl";
 			reg = <0x01010000 0x300000>;
 			interrupts = <GIC_SPI 208 IRQ_TYPE_LEVEL_HIGH>;