mtd: spi-nor: Avoid locking/unlocking unrequested memory blocks

commit b588feb2431f521cc4cd96c923675a38bcb6295c from
https://github.com/Xilinx/linux-xlnx.git

 xlnx_rebase_v6.1

As per the current flash lock/unlock logic the status register was getting
written twice, during the 1st SR write the framework sets the correct Block
Protection value, but immediately this value gets overwritten by another
value which causes the entire flash to get locked/unlocked. Updated the
flash lock/unlock logic to avoid overwriting the status register.
Updated the flash_info structure of supported flash parts with the
appropriate Block Protection flags.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
State: pending
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>