mtd: rawnand: cadence: remove a redundant dev_err call

There is an error message within devm_ioremap_resource already, so
remove the dev_err call to avoid a redundant error message.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200921013805.1724606-1-liushixin2@huawei.com