ARM: dts: rockchip: Add missing dma-names SPI support for rv1108

Pass the 'dma-names' property to the SPI ports so that DMA can
be supported.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rv1108.dtsi

@@ -207,6 +207,7 @@ spi: spi@10270000 {
 		clocks = <&cru SCLK_SPI>, <&cru PCLK_SPI>;
 		clock-names = "spiclk", "apb_pclk";
 		dmas = <&pdma 8>, <&pdma 9>;
+		dma-names = "tx", "rx";
 		#dma-cells = <2>;
 		#address-cells = <1>;
 		#size-cells = <0>;