spi: dw-mid: convert to use dw_dmac instead of intel_mid_dma

intel_mid_dma seems to be unmaintained for a long time. Moreover, the IP block
of DMA itself is the same in both dw_dmac and intel_mid_dma. This patch moves
spi-dw-midpci to use dw_dmac driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index f298df5..41f77e2 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -128,10 +128,10 @@
 	struct dma_chan		*txchan;
 	struct dma_chan		*rxchan;
 	unsigned long		dma_chan_busy;
-	struct device		*dma_dev;
 	dma_addr_t		dma_addr; /* phy address of the Data register */
 	struct dw_spi_dma_ops	*dma_ops;
-	void			*dma_priv; /* platform relate info */
+	void			*dma_tx;
+	void			*dma_rx;
 
 	/* Bus interface info */
 	void			*priv;