mtd: spi-nor: Add a post BFPT fixup for MX25L25635E

MX25L25635F and MX25L25635E share the same JEDEC-ID, but the F variant
supports 4-byte opcodes while the E variant doesn't. We need a way to
differentiate those 2 chips and set the SNOR_F_4B_OPCODES flag only for
the F variant.

Luckily, 4-byte opcode support is not the only difference: Fast Read
4-4-4 is only supported by the F variant, and this feature is
advertised in the BFPT table. Use this to decide when to set the
SNOR_F_4B_OPCODES flag.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>