mtd: spi-nor: Enable locking for n25q128a11

As 4bit block protection patchset for some micron models are merged,
n25q128a11 also uses 4 bit Block Protection scheme, so enable locking
for it. Tested it on n25q128a11, the locking functions work well.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: Jungseung Lee <js07.lee@samsung.com>
Tested-by: Shreyas Joshi <shreyasjoshi15@gmail.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>