ARM: imx: move clk_prepare() out from mxc_restart()

It's inappropriate to call clk_prepare() in mxc_restart(), because the
restart routine could be called in atomic context.  Move clk_get() and
clk_prepare() into mxc_arch_reset_init() and only have the atomic part
clk_enable() be called in mxc_restart().

As a result, mxc_arch_reset_init() needs to be called after clk gets
initialized.

While there, it also changes printk(KERN_ERR ...) to pr_err() and adds
__init annotation for mxc_arch_reset_init().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

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

@@ -16,10 +16,13 @@
 #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));
+
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }