uboot-imx

sf: Return bank_sel, if flash->bank_curr == bank_sel

If computed bank_sel is same as flash->bank_curr which is
computed at probe time, then return the bank_sel instead of zero.

Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>