sandbox: Add OS dependent layer

We want to keep all OS-dependent code in once place, with a simple interface
to U-Boot. For now, this is that place.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index 554cae8..c7bf8a9 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -20,15 +20,14 @@
  */
 
 #include <common.h>
+#include <os.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
-	/*
-	 * This is considered normal termination for now. We wil call os_exit()
-	 * when available.
-	 */
+	/* This is considered normal termination for now */
+	os_exit(0);
 	return 0;
 }