spi: dw: Avoid useless assignments in generic DMA setup

Generic DMA setup doesn't rely on certain type of DMA controller and thus
shouldn't use Intel Medfield settings, although it's harmless in this case.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200507115449.8093-1-andriy.shevchenko@linux.intel.comSigned-off-by: NMark Brown <broonie@kernel.org>

drivers/spi/spi-dw-mid.c

@@ -321,8 +321,6 @@ static const struct dw_spi_dma_ops generic_dma_ops = {
 
 static void dw_spi_mid_setup_dma_generic(struct dw_spi *dws)
 {
-	dws->dma_tx = &mid_dma_tx;
-	dws->dma_rx = &mid_dma_rx;
 	dws->dma_ops = &generic_dma_ops;
 }
 #else	/* CONFIG_SPI_DW_MID_DMA */