uboot-imx

sf: probe: Add support to clear flash BP# bits

Few of the flashes(Atmel, Macronix and SST) require to
clear BP# bits in flash power ups.

So clear these BP# bits at probe time, so-that the flash
is ready for user operations.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>