phy: marvell: a3700: Update compatible string to official DT bindings

In commit d368e1070514 ("phy: marvell: a3700: Convert to official DT
bindings in COMPHY driver") was done update to official DT bindings but
compatible string of official DT bindings was not updated.

Fix it now.

Fixes: d368e1070514 ("phy: marvell: a3700: Convert to official DT bindings in COMPHY driver")
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-37xx.dtsi b/arch/arm/dts/armada-37xx.dtsi
index bef6ef0..b363212 100644
--- a/arch/arm/dts/armada-37xx.dtsi
+++ b/arch/arm/dts/armada-37xx.dtsi
@@ -313,7 +313,7 @@
 			};
 
 			comphy: comphy@18300 {
-				compatible = "marvell,mvebu-comphy", "marvell,comphy-armada-3700";
+				compatible = "marvell,comphy-a3700";
 				reg = <0x18300 0x28>,
 				      <0x1f300 0x3d000>;
 				#address-cells = <1>;