ARM: imx: create mxc_arch_reset_init_dt() for DT boot

The mxc_arch_reset_init() uses static mapping and calls clk_get_sys() to
get clock.  It's suitable for non-DT boot but not for DT boot where
dynamic mapping and of_clk_get() should be used instead.  Create
mxc_arch_reset_init_dt() as the DT variant of mxc_arch_reset_init(),
and change DT platforms to use it.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/imx31-dt.c b/arch/arm/mach-imx/imx31-dt.c
index d8b3b22..818a1cc 100644
--- a/arch/arm/mach-imx/imx31-dt.c
+++ b/arch/arm/mach-imx/imx31-dt.c
@@ -16,12 +16,11 @@
 #include <asm/mach/time.h>
 
 #include "common.h"
-#include "hardware.h"
 #include "mx31.h"
 
 static void __init imx31_dt_init(void)
 {
-	mxc_arch_reset_init(MX31_IO_ADDRESS(MX31_WDOG_BASE_ADDR));
+	mxc_arch_reset_init_dt();
 
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }