spi: dw: Discard chip enabling on DMA setup error

It's pointless to enable the chip back if the DMA setup procedure fails,
since we'll disable it on the next transfer anyway. For the same reason We
don't do that in case of a failure detected in any other methods called
from the transfer_one() method.

While at it consider any non-zero value returned from the dma_setup
callback to be erroneous as it's supposed to be in the kernel.
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201007235511.4935-13-Sergey.Semin@baikalelectronics.ruSigned-off-by: NMark Brown <broonie@kernel.org>

drivers/spi/spi-dw-core.c

@@ -372,10 +372,8 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 
 	if (dws->dma_mapped) {
 		ret = dws->dma_ops->dma_setup(dws, transfer);
-		if (ret < 0) {
-			spi_enable_chip(dws, 1);
+		if (ret)
 			return ret;
-		}
 	}
 
 	spi_enable_chip(dws, 1);