Merge tag 'spi-nor/for-7.2' into mtd/next

SPI NOR changes for 7.2

Notable changes:

- Big set of cleanups and improvements to the locking support. This
  series contains some cleanups and bug fixes for code and documentation
  around write protection. Then support is added for complement locking,
  which allows finer grained configuration of what is considered locked
  and unlocked. Then complement locking is enabled on a bunch of Winbond
  W25 flashes.

- Fix die erase support on Spansion flashes. Die erase is only supported
  on multi-die flashes, but the die erase opcode was set for all. When
  the opcode is set, it overrides the default chip erase opcode which
  should be used for single-die flashes. Only set the opcode on
  multi-die flashes. Also, the opcode was not set on multi-die s28hx-t
  flashes. Set it so they can use die-erase correctly.