mtd: spinand: Add initial support for the MX35LF2GE4AB chip

Add support for the MX35LF2GE4AB chip, which is similar to its cousin
MX35LF1GE4AB, with two planes instead of one.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jagan Teki <jagan@openedev.com>