mtd: nand: remove useless fields from pxa3xx NAND platform data

mtd: nand: remove useless fields from pxa3xx NAND platform data

The "enable arbiter" bit is available only for pxa3xx based platforms
but it was experimentally shown that even if this bit is reserved,
some Marvell platforms (64-bit) actually need it to be set. The driver
always set this bit regardless of this property, which is harmless.
Then this property is not needed.

The "num_cs" field is always 1 and for a good reason, the old driver
(pxa3xx_nand.c) could only handle one. The new driver that replaces it
(marvell_nand.c) can handle more, but better use device tree for such
description. As there is only one available chip select, there is no
need for an array of partitions neither an array of partition numbers.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>