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/board/phytium/durian/durian.c b/board/phytium/durian/durian.c
index 59f307d..40dd27a 100644
--- a/board/phytium/durian/durian.c
+++ b/board/phytium/durian/durian.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <asm/armv8/mmu.h>
 #include <asm/system.h>
 #include <asm/io.h>