mtd: rawnand: brcmnand: fix style issues

Fix various style issues.

Signed-off-by: David Regan <dregan@broadcom.com>
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240223034758.13753-3-william.zhang@broadcom.com