mtd: rawnand: qcom: Release resources on failure within qcom_nandc_alloc()

In case when DMA channel request or alloc_bam_transaction() fails,
dma_unmap_single() and any channels already requested should be released.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200227123749.24064-6-peter.ujfalusi@ti.com