staging: mt7621-dts: avoid warnings in pinctrl definitions

The device-tree checking code sees node names "i2c" and "spi" in the
pinctrl definition and thinks these are defining i2c or spi devices,
and complains that they look wrong.

So add a '0' to the end of each name (much like "uart" and "rgmii"
have numbers at the end) to avoid the warning.

Signed-off-by: NeilBrown <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/mt7621-dts/mt7621.dtsi

···
 		state_default: pinctrl0 {
 		};
 
-		i2c_pins: i2c {
-			i2c {
+		i2c_pins: i2c0 {
+			i2c0 {
 				group = "i2c";
 				function = "i2c";
 			};
 		};
 
-		spi_pins: spi {
-			spi {
+		spi_pins: spi0 {
+			spi0 {
 				group = "spi";
 				function = "spi";
 			};
···
 			};
 		};
 
-		mdio_pins: mdio {
-			mdio {
+		mdio_pins: mdio0 {
+			mdio0 {
 				group = "mdio";
 				function = "mdio";
 			};
 		};
 
-		pcie_pins: pcie {
-			pcie {
+		pcie_pins: pcie0 {
+			pcie0 {
 				group = "pcie";
 				function = "pcie rst";
 			};
 		};
 
-		nand_pins: nand {
+		nand_pins: nand0 {
 			spi-nand {
 				group = "spi";
 				function = "nand1";
···
 			};
 		};
 
-		sdhci_pins: sdhci {
-			sdhci {
+		sdhci_pins: sdhci0 {
+			sdhci0 {
 				group = "sdhci";
 				function = "sdhci";
 			};