mtd: spinand: gigadevice: fix Quad IO for GD5F1GQ5UExxG

mtd: spinand: gigadevice: fix Quad IO for GD5F1GQ5UExxG

[ Upstream commit a4f9dd55c5e1bb951db6f1dee20e62e0103f3438 ]

Read From Cache Quad IO (EBH) uses 2 dummy bytes on this chip according
to page 23 of the datasheet[0].

[0]: https://www.gigadevice.com/datasheet/gd5f1gq5xexxg/

Fixes: 469b99248985 ("mtd: spinand: gigadevice: Support GD5F1GQ5UExxG")
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220320100001.247905-2-gch981213@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>