arm: dts: rz-g2-beacon-u-boot: Fix QSPI Regression

The QSPI is accessed via the RPC-IF, but the compatible flags
previously used a different name.  This compatibel name was changed
which broke the ability to access the QSPI.  Fix this by removing
the custom naming reference.

Fixes: 68083b89 ("renesas: Fix RPC-IF compatible values")
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@gmail.com>

arch/arm/dts/rz-g2-beacon-u-boot.dtsi

@@ -45,7 +45,6 @@
 };
 
 &rpc {
-	compatible = "renesas,rcar-gen3-rpc";
 	pinctrl-0 = <&qspi_pins>;
 	pinctrl-names = "default";
 	num-cs = <1>;