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>

drivers/mtd/spi/Kconfig

@@ -34,6 +34,21 @@ config SPI_FLASH
 
 	  If unsure, say N
 
+config SPI_FLASH_DATAFLASH
+	bool "AT45xxx DataFlash support"
+	depends on SPI_FLASH && DM_SPI_FLASH
+	help
+	  Enable the access for SPI-flash-based AT45xxx DataFlash chips.
+	  DataFlash is a kind of SPI flash. Most AT45 chips have two buffers
+	  in each chip, which may be used for double buffered I/O; but this
+	  driver doesn't (yet) use these for any kind of i/o overlap or prefetching.
+
+	  Sometimes DataFlash is packaged in MMC-format cards, although the
+	  MMC stack can't (yet?) distinguish between MMC and DataFlash
+	  protocols during enumeration.
+
+	  If unsure, say N
+
 config SPI_FLASH_MTD
 	bool "SPI Flash MTD support"
 	depends on SPI_FLASH

drivers/mtd/spi/sf_dataflash.c

@@ -19,16 +19,6 @@
 
 #include "sf_internal.h"
 
-/*
- * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
- * each chip, which may be used for double buffered I/O; but this driver
- * doesn't (yet) use these for any kind of i/o overlap or prefetching.
- *
- * Sometimes DataFlash is packaged in MMC-format cards, although the
- * MMC stack can't (yet?) distinguish between MMC and DataFlash
- * protocols during enumeration.
- */
-
 /* reads can bypass the buffers */
 #define OP_READ_CONTINUOUS	0xE8
 #define OP_READ_PAGE		0xD2