mtd: nand: zynq: Add support for the NAND lock/unlock operation

Zynq NAND driver is not support for NAND lock or unlock operation.
Hence, accidentally write into the critical NAND region might cause
data corruption to occur.

This commit is to add NAND lock/unlock command into NAND SMC register
set for NAND lock/unlock operaion.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Keng Soon Cheah <keng.soon.cheah@ni.com>
Cc: Chen Yee Chew <chen.yee.chew@ni.com>
Cc: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Scott Wood <oss@buserror.net>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>