mtd: rawnand: brcmnand: read/write oob during EDU transfer

Added support to read/write oob during EDU transfers.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210311170909.9031-1-kdasu.kdev@gmail.com