dm: sandbox: Add os_localtime() to obtain the system time

Add a function to read the system time into U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/os.h

@@ -13,6 +13,7 @@
 
 #include <linux/types.h>
 
+struct rtc_time;
 struct sandbox_state;
 
 /**
@@ -277,4 +278,14 @@ int os_read_ram_buf(const char *fname);
  */
 int os_jump_to_image(const void *dest, int size);
 
+/**
+ * Read the current system time
+ *
+ * This reads the current Local Time and places it into the provided
+ * structure.
+ *
+ * @param rt		Place to put system time
+ */
+void os_localtime(struct rtc_time *rt);
+
 #endif