i.MX3: Fix compiler warnings

Fix some base address declaration by adding a cast.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mx3/iomux.c b/arch/arm/mach-mx3/iomux.c
index 3dda1fe..6e664be 100644
--- a/arch/arm/mach-mx3/iomux.c
+++ b/arch/arm/mach-mx3/iomux.c
@@ -43,7 +43,8 @@
  */
 int mxc_iomux_mode(unsigned int pin_mode)
 {
-	u32 reg, field, l, mode, ret = 0;
+	u32 field, l, mode, ret = 0;
+	void __iomem *reg;
 
 	reg = IOMUXSW_MUX_CTL + (pin_mode & IOMUX_REG_MASK);
 	field = pin_mode & 0x3;
@@ -70,7 +71,8 @@
  */
 void mxc_iomux_set_pad(enum iomux_pins pin, u32 config)
 {
-	u32 reg, field, l;
+	u32 field, l;
+	void __iomem *reg;
 
 	reg = IOMUXSW_PAD_CTL + (pin + 2) / 3;
 	field = (pin + 2) % 3;