arm64: dts: renesas: r8a7795: add missing dma-names on hscif2

hscif2 has 4 dmas, but has only 2 dma-names.
This patch add missing dma-names.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: e0f0bda7 ("arm64: dts: renesas: r8a7795: sort subnodes
of the soc node")
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795.dtsi

@@ -652,7 +652,7 @@ hscif2: serial@e6560000 {
 			clock-names = "fck", "brg_int", "scif_clk";
 			dmas = <&dmac1 0x35>, <&dmac1 0x34>,
 			       <&dmac2 0x35>, <&dmac2 0x34>;
-			dma-names = "tx", "rx";
+			dma-names = "tx", "rx", "tx", "rx";
 			power-domains = <&sysc R8A7795_PD_ALWAYS_ON>;
 			resets = <&cpg 518>;
 			status = "disabled";