lantiq: VGV7519 - cleanup pinmux configuration

Cleanup the pinmux configuration by removing the unused spi node. Nothing is connected to the SPI bus on devices.

The stp_out pinmux child node covers the same GPIOs as the already used
stp group.

The same applies to the gphy-leds_out pinmux node and the "gphy0
led1" as well as "gphy1 led0" groups.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/lantiq/dts/VGV7519.dtsi

@@ -53,26 +53,14 @@
 				stp {
 					lantiq,groups = "stp";
 					lantiq,function = "stp";
-				};
-				spi {
-					lantiq,groups = "spi_di", "spi_do", "spi_clk";
-					lantiq,function = "spi";
+					lantiq,open-drain = <0>;
+					lantiq,output = <1>;
+					lantiq,pull = <0>;
 				};
 				mdio {
 					lantiq,groups = "mdio";
 					lantiq,function = "mdio";
 				};
-				gphy-leds_out {
-					lantiq,pins = "io7", "io44";
-					lantiq,pull = <0>;
-					lantiq,output = <1>;
-				};
-				stp_out {
-					lantiq,pins = "io4", "io5", "io6";
-					lantiq,open-drain = <0>;
-					lantiq,output = <1>;
-					lantiq,pull = <0>;
-				};
 				pci-rst {
 					lantiq,pins = "io21";
 					lantiq,open-drain = <0>;