ARM: imx: use dynamic mapping for timer

Pass physical address of timer block to mxc_timer_init() call, which in
turn does dynamic mapping within the function.  Thus, we can avoid using
static mapping in clock drivers.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c
index 15d18e1..acb1ff5 100644
--- a/arch/arm/mach-imx/time.c
+++ b/arch/arm/mach-imx/time.c
@@ -344,12 +344,13 @@
 	setup_irq(irq, &mxc_timer_irq);
 }
 
-void __init mxc_timer_init(void __iomem *base, int irq)
+void __init mxc_timer_init(unsigned long pbase, int irq)
 {
 	struct clk *clk_per = clk_get_sys("imx-gpt.0", "per");
 	struct clk *clk_ipg = clk_get_sys("imx-gpt.0", "ipg");
 
-	timer_base = base;
+	timer_base = ioremap(pbase, SZ_4K);
+	BUG_ON(!timer_base);
 
 	_mxc_timer_init(irq, clk_per, clk_ipg);
 }