ARM: imx31: Retrieve the IIM base address from devicetree

Now that imx31 has been converted to a devicetree-only platform,
retrieve the IIM base address from devicetree.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/cpu-imx31.c

@@ -6,6 +6,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/of_address.h>
 #include <linux/io.h>
 
 #include "common.h"
@@ -32,10 +33,16 @@ static struct {
 
 static int mx31_read_cpu_rev(void)
 {
+	void __iomem *iim_base;
+	struct device_node *np;
 	u32 i, srev;
 
+	np = of_find_compatible_node(NULL, NULL, "fsl,imx31-iim");
+	iim_base = of_iomap(np, 0);
+	BUG_ON(!iim_base);
+
 	/* read SREV register from IIM module */
-	srev = imx_readl(MX31_IO_ADDRESS(MX31_IIM_BASE_ADDR + MXC_IIMSREV));
+	srev = imx_readl(iim_base + MXC_IIMSREV);
 	srev &= 0xff;
 
 	for (i = 0; i < ARRAY_SIZE(mx31_cpu_type); i++)