arm64: dts: renesas: r8a77965: Remove reg-names of display node

Remove the "reg-names" property from the display node of R-Car Gen3 R8A77965
device tree.

No other mainline R-Car Gen3 SoC has that property specified.

Fixes: 2f2c71bf ("arm64: dts: renesas: r8a77965: Populate the DU instance placeholder")
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[reworded commit message, sent upstream]
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77965.dtsi

@@ -2447,7 +2447,6 @@ port@1 {
 		du: display@feb00000 {
 			compatible = "renesas,du-r8a77965";
 			reg = <0 0xfeb00000 0 0x80000>;
-			reg-names = "du";
 			interrupts = <GIC_SPI 256 IRQ_TYPE_LEVEL_HIGH>,
 				     <GIC_SPI 268 IRQ_TYPE_LEVEL_HIGH>,
 				     <GIC_SPI 270 IRQ_TYPE_LEVEL_HIGH>;