mtd: spi-nor: cadence-quadspi: Don't initialize rx_dma_complete on failure

mtd: spi-nor: cadence-quadspi: Don't initialize rx_dma_complete on failure

[ Upstream commit 4a609e4b9be1e479846a99e36be54bfb24ad2504 ]

If driver fails to acquire DMA channel then don't initialize
rx_dma_complete struct as it won't be used.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-4-vigneshr@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Stable-dep-of: 2087e85bb66e ("spi: cadence-quadspi: fix suspend-resume implementations")
Signed-off-by: Sasha Levin <sashal@kernel.org>