ARM64: dts: meson-gxbb: add SCPI pre-1.0 compatible

The SCPI driver has an updated compatible to indicate the pre-released
(pre v1.0) status of the driver.  Since Amlogic used a pre-1.0
version, add that compatible as well.
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi

@@ -51,7 +51,7 @@ / {
 	compatible = "amlogic,meson-gxbb";
 
 	scpi {
-		compatible = "amlogic,meson-gxbb-scpi";
+		compatible = "amlogic,meson-gxbb-scpi", "arm,scpi-pre-1.0";
 		mboxes = <&mailbox 1 &mailbox 2>;
 		shmem = <&cpu_scp_lpri &cpu_scp_hpri>;