mtd: spi-nor: winbond: Fix 4-byte opcode support for w25q256

There are 2 different chips (w25q256fv and w25q256jv) that share
the same JEDEC ID. Only w25q256jv fully supports 4-byte opcodes.
Use SFDP header version to differentiate between them.

Fixes: 10050a02 ("mtd: spi-nor: Add 4B_OPCODES flag to w25q256")
Signed-off-by: Mantas Pucka <mantas@8devices.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>