spi: spi-dw: fix all sparse warnings

The dw_{read,write}[lw] macros produce sparse warnings everytime they
are used.  The "read" ones cause:

warning: cast removes address space of expression
warning: incorrect type in argument 1 (different address spaces)
   expected void const volatile [noderef] <asn:2>*addr
   got unsigned int *<noident>

And the "write" ones:

warning: cast removes address space of expression
warning: incorrect type in argument 2 (different address spaces)
   expected void volatile [noderef] <asn:2>*addr
   got unsigned int *<noident>

Fix this by removing struct dw_spi_reg and converting all the register
offsets to #defines. Then convert the macros into inlined functions so
that proper type checking can occur.

While here, also fix the three sparse warnings in spi-dw-mid.c due to
the return value of ioremap_nocache being stored in a u32 * not a
void __iomem *.

With these changes the spi-dw* files all build with no sparse warnings.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index 130e555..e743a45 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -116,13 +116,13 @@
 	/* 1. setup DMA related registers */
 	if (cs_change) {
 		spi_enable_chip(dws, 0);
-		dw_writew(dws, dmardlr, 0xf);
-		dw_writew(dws, dmatdlr, 0x10);
+		dw_writew(dws, DW_SPI_DMARDLR, 0xf);
+		dw_writew(dws, DW_SPI_DMATDLR, 0x10);
 		if (dws->tx_dma)
 			dma_ctrl |= 0x2;
 		if (dws->rx_dma)
 			dma_ctrl |= 0x1;
-		dw_writew(dws, dmacr, dma_ctrl);
+		dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
 		spi_enable_chip(dws, 1);
 	}
 
@@ -200,7 +200,8 @@
 
 int dw_spi_mid_init(struct dw_spi *dws)
 {
-	u32 *clk_reg, clk_cdiv;
+	void __iomem *clk_reg;
+	u32 clk_cdiv;
 
 	clk_reg = ioremap_nocache(MRST_CLK_SPI0_REG, 16);
 	if (!clk_reg)