ramips: fix rt3883 pinmux for second SPI

The rt3883 doesn't have a pinmux group named spi_cs1. The cs1 is part
of the pci group. The function pci-func enables the second chip select.

Signed-off-by: Mathias Kresin <[email protected]>

target/linux/ramips/dts/rt3883.dtsi

@@ -295,8 +295,8 @@
 
 		spi_cs1: spi1 {
 			spi1 {
-				ralink,group = "spi_cs1";
-				ralink,function = "spi_cs1";
+				ralink,group = "pci";
+				ralink,function = "pci-func";
 			};
 		};