dts: switch spi-flash to jedec, spi-nor compatible

There is no reason not to use the Linux "jedec,spi-nor" binding in U-Boot
dts files. This compatible has been added in sf_probe, let use it.

This patch switches to jedec,spi-nor when spi-flash is used in the DTS
and DTSI files, and removed spi-flash when jedec,spi-nor is already
present.

The x86 dts are switched in a separate commit since it depends on a change
in fdtdec.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Evgeniy Paltsev <paltsev@synopsys.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Patrick Delaunay <Patrick.delaunay@st.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/arch/arm/dts/imx6ull-14x14-evk.dts b/arch/arm/dts/imx6ull-14x14-evk.dts
index 8a1b67d..9ebcfe1 100644
--- a/arch/arm/dts/imx6ull-14x14-evk.dts
+++ b/arch/arm/dts/imx6ull-14x14-evk.dts
@@ -455,7 +455,7 @@
 		#address-cells = <1>;
 		#size-cells = <1>;
 		/* compatible = "micron,n25q256a"; */
-		compatible = "spi-flash";
+		compatible = "jedec,spi-nor";
 		spi-max-frequency = <29000000>;
 		spi-nor,ddr-quad-read-dummy = <6>;
 		reg = <0>;