mtd: rawnand: cadence: fix error code in cadence_nand_init()

Replace dma_request_channel() with dma_request_chan_by_mask() and use
helper functions to return proper error code instead of fixed -EBUSY.

Fixes: ec4ba01e ("mtd: rawnand: Add new Cadence NAND driver to MTD subsystem")
Cc: stable@vger.kernel.org
Signed-off-by: Niravkumar L Rabara <niravkumar.l.rabara@intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>