arm64: tegra: Remove unused only-1-8-v properties

The only-1-8-v property is not support by an DT schema, so drop it.
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra234-p3701-0000.dtsi

@@ -11,7 +11,6 @@ mmc@3460000 {
 			status = "okay";
 			bus-width = <8>;
 			non-removable;
-			only-1-8-v;
 		};
 
 		rtc@c2a0000 {

arch/arm64/boot/dts/nvidia/tegra234-sim-vdk.dts

@@ -26,7 +26,6 @@ mmc@3460000 {
 			status = "okay";
 			bus-width = <8>;
 			non-removable;
-			only-1-8-v;
 		};
 
 		rtc@c2a0000 {