mtd: SST25L (non JEDEC) SPI Flash driver

Add support for the non JEDEC SST25L SPI Flash devices.

[dwmw2: Some cleanups]

Signed-off-by: Andre Renaud <andre@bluewatersys.com>
Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: "H Hartley Sweeten" <hartleys@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>