Now the "spi-flash" compatible has been removed in the DTS files,
remove this compatible from sf_probe to finally use the Linux "jedec,spi-nor"
compatible.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> Reviewed-by: Jagan Teki <jagan@openedev.com>