mtd: rawnand: rockchip: fix platform_get_irq.cocci warning

Remove dev_err() messages after platform_get_irq*() failures.
platform_get_irq() already prints an error.

Generated by: scripts/coccinelle/api/platform_get_irq.cocci

Signed-off-by: Yihao Han <hanyihao@vivo.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220303123431.3170-1-hanyihao@vivo.com