cmd: mtd: OTP access support

cmd: mtd: OTP access support

Add access to OTP region. It supports info, dump, write and lock
operations. Usage example:

'mtd otpread nand0 u 0 1024' - dump 1024 bytes of user area starting
 from offset 0 of device 'nand0'.

'mtd otpwrite nand0 10 11223344' - write binary data 0x11, 0x22, 0x33,
 0x44 to offset 10 to user area of device 'nand0'.

'mtd otplock nand0 0 1024' - lock 1024 bytes of user area starting
 from offset 0 of device 'nand0'.

'mtd otpinfo nand0 f' - show info about factory area of device 'nand0'.

Link: https://lore.kernel.org/all/20240326223919.3781-1-avkrasnov@salutedevices.com
Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>