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>