dts: versatile: add pl180 compatible strings

While not needed for probing, add the "arm,pl180" compatible string for
completeness.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/versatile-ab.dts

@@ -187,7 +187,7 @@ aaci@4000 {
 				interrupts = <24>;
 			};
 			mmc@5000 {
-				compatible = "arm,primecell";
+				compatible = "arm,pl180", "arm,primecell";
 				reg = < 0x5000 0x1000>;
 				interrupts-extended = <&vic 22 &sic 2>;
 			};

arch/arm/boot/dts/versatile-pb.dts

@@ -39,7 +39,7 @@ sci@a000 {
 				interrupts = <5>;
 			};
 			mmc@b000 {
-				compatible = "arm,primecell";
+				compatible = "arm,pl180", "arm,primecell";
 				reg = <0xb000 0x1000>;
 				interrupts-extended = <&vic 23 &sic 2>;
 			};