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/drivers/sysreset/sysreset-uclass.c b/drivers/sysreset/sysreset-uclass.c
index 3920258..8eff603 100644
--- a/drivers/sysreset/sysreset-uclass.c
+++ b/drivers/sysreset/sysreset-uclass.c
@@ -7,6 +7,7 @@
 #define LOG_CATEGORY UCLASS_SYSRESET
 
 #include <common.h>
+#include <cpu_func.h>
 #include <sysreset.h>
 #include <dm.h>
 #include <errno.h>