mtd: rawnand: cadence: Remove dev_err() on platform_get_irq() failure

platform_get_irq() will call dev_err() itself on failure,
so there is no need for the driver to also do this.
This is detected by coccinelle.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>