arm64: dts: imx8m: add fsl,stop-mode property for FEC

Add fsl,stop-mode property for FEC to enable stop mode.
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm.dtsi

@@ -930,6 +930,7 @@ fec1: ethernet@30be0000 {
 				nvmem-cells = <&fec_mac_address>;
 				nvmem-cell-names = "mac-address";
 				nvmem_macaddr_swap;
+				fsl,stop-mode = <&gpr 0x10 3>;
 				status = "disabled";
 			};
 

arch/arm64/boot/dts/freescale/imx8mn.dtsi

@@ -928,6 +928,7 @@ fec1: ethernet@30be0000 {
 				nvmem-cells = <&fec_mac_address>;
 				nvmem-cell-names = "mac-address";
 				nvmem_macaddr_swap;
+				fsl,stop-mode = <&gpr 0x10 3>;
 				status = "disabled";
 			};
 

arch/arm64/boot/dts/freescale/imx8mp.dtsi

@@ -782,6 +782,7 @@ fec: ethernet@30be0000 {
 				fsl,num-rx-queues = <3>;
 				nvmem-cells = <&eth_mac1>;
 				nvmem-cell-names = "mac-address";
+				fsl,stop-mode = <&gpr 0x10 3>;
 				nvmem_macaddr_swap;
 				status = "disabled";
 			};

arch/arm64/boot/dts/freescale/imx8mq.dtsi

@@ -1190,6 +1190,7 @@ fec1: ethernet@30be0000 {
 				nvmem-cells = <&fec_mac_address>;
 				nvmem-cell-names = "mac-address";
 				nvmem_macaddr_swap;
+				fsl,stop-mode = <&iomuxc_gpr 0x10 3>;
 				status = "disabled";
 			};
 		};