mt25qu256a [1] uses the 4 bit Block Protection scheme and supports
Top/Bottom protection via the BP and TB bits of the Status Register.
BP3 is located in bit 6 of the Status Register.
Tested on MT25QU256ABA8ESF-0SIT.
[1] https://www.micron.com/-/media/client/global/documents/products/data-sheet/nor-flash/serial-nor/mt25q/die-rev-a/mt25q_qljs_u_256_aba_0.pdf
Signed-off-by: Eliav Farber <farbere@xxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20221019071631.15191-1-farbere@xxxxxxxxxx