lantiq: VGV7510KW22/VGV7519 update spi pinmux group

With the backport of the kernel 4.5 pinctrl-xway patches (3551609d &
826bca29) the pinmux group "spi" was splitted into "spi_di", "spi_do" &
"spi_clk". But the no longer existing group "spi" is still used by some
device tree source files.

This fixes the detection of the wireless chipset of the VGV7510KW22.

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

SVN-Revision: 48658

target/linux/lantiq/dts/VGV7510KW22.dtsi

@@ -74,7 +74,7 @@
 					lantiq,output = <1>;
 				};
 				spi {
-					lantiq,groups = "spi";
+					lantiq,groups = "spi_di", "spi_do", "spi_clk";
 					lantiq,function = "spi";
 				};
 			};

target/linux/lantiq/dts/VGV7519.dtsi

@@ -53,7 +53,7 @@
 					lantiq,function = "stp";
 				};
 				spi {
-					lantiq,groups = "spi";
+					lantiq,groups = "spi_di", "spi_do", "spi_clk";
 					lantiq,function = "spi";
 				};
 				mdio {