spi: sprd: Release DMA channel also on probe deferral

If dma_request_chan() for TX channel fails with EPROBE_DEFER, the RX
channel would not be released and on next re-probe it would be requested
second time.

Fixes: 386119bc ("spi: sprd: spi: sprd: Add DMA mode support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/20200901152713.18629-1-krzk@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>