common, menu: use abortboot for menu timeout

Signed-off-by: Jason Hobbs <jason.hobbs@calxeda.com>

include/common.h

@@ -260,6 +260,9 @@ int	readline_into_buffer	(const char *const prompt, char * buffer);
 int	parse_line (char *, char *[]);
 void	init_cmd_timeout(void);
 void	reset_cmd_timeout(void);
+#ifdef CONFIG_MENU
+int	abortboot(int bootdelay);
+#endif
 
 /* arch/$(ARCH)/lib/board.c */
 void	board_init_f  (ulong) __attribute__ ((noreturn));