uboot-imx

sf: Kconfig: Add SPI_FLASH_DATAFLASH entry

Added SPI_FLASH_DATAFLASH entry on Kconfig with help description.

data flash driver comes with good decription, hence moved the
same on to kconfig help decription.

Signed-off-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Haikun Wang <haikun.wang@freescale.com>