mtd: rawnand: omap2: fix force_8bit flag behaviour for DMA mode

In DMA mode we were not considering the force_8bit flag.

Fix it by using regular non-DMA 8-bit I/O if force_8bit flag is set.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211209090458.24830-6-rogerq@kernel.org