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/cpu/armv7/stv0991/reset.c b/arch/arm/cpu/armv7/stv0991/reset.c
index d4b3ab7..008e271 100644
--- a/arch/arm/cpu/armv7/stv0991/reset.c
+++ b/arch/arm/cpu/armv7/stv0991/reset.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <asm/io.h>
 #include <asm/arch/stv0991_wdru.h>
 void reset_cpu(ulong ignored)