ARM: mvebu: add "spi-flash" compatible string

U-boots spi-nor support is currently considered a work in progress. For
now to avoid issues it is necessary to add a "spi-flash" compatible
string. Eventually the "jedec,spi-nor" will be sufficient when the core
U-boot code is updated to support it.
Signed-off-by: NChris Packham <judge.packham@gmail.com>
Reviewed-by: NJagan Teki <jagan@openedev.com>
Signed-off-by: NStefan Roese <sr@denx.de>

arch/arm/dts/armada-385-amc.dts

@@ -154,7 +154,7 @@
 		u-boot,dm-pre-reloc;
 		#address-cells = <1>;
 		#size-cells = <1>;
-		compatible = "st,m25p128", "jedec,spi-nor";
+		compatible = "st,m25p128", "jedec,spi-nor", "spi-flash";
 		reg = <0>; /* Chip select 0 */
 		spi-max-frequency = <50000000>;
 		m25p,fast-read;