ARM: dts: BCM5301X: Fix pinmux subnodes names

This matches pinmux-node.yaml requirements.

Signed-off-by: Rafał Miłecki <[e-mail]>
Signed-off-by: Florian Fainelli <[e-mail]>

arch/arm/boot/dts/bcm47094.dtsi

···
 &pinctrl {
 	compatible = "brcm,bcm4709-pinmux";
 
-	pinmux_mdio: mdio {
+	pinmux_mdio: mdio-pins {
 		groups = "mdio_grp";
 		function = "mdio";
 	};

arch/arm/boot/dts/bcm5301x.dtsi

···
 					function = "spi";
 				};
 
-				pinmux_i2c: i2c {
+				pinmux_i2c: i2c-pins {
 					groups = "i2c_grp";
 					function = "i2c";
 				};
 
-				pinmux_pwm: pwm {
+				pinmux_pwm: pwm-pins {
 					groups = "pwm0_grp", "pwm1_grp",
 						 "pwm2_grp", "pwm3_grp";
 					function = "pwm";
 				};
 
-				pinmux_uart1: uart1 {
+				pinmux_uart1: uart1-pins {
 					groups = "uart1_grp";
 					function = "uart1";
 				};