common: Move reset_cpu() to the CPU header

Move this function out of common.h and into a relevant header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/lib/interrupts_m.c b/arch/arm/lib/interrupts_m.c
index e4373f3..1f6fdf2 100644
--- a/arch/arm/lib/interrupts_m.c
+++ b/arch/arm/lib/interrupts_m.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <irq_func.h>
 
 /*