kconfig: use va_end to match corresponding va_start

Although on some systems va_end is a no-op, it is good practice
to use va_end, especially since the manual states:

"Each invocation of va_start() must be matched by a corresponding
invocation of va_end() in the same function."

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

Change-Id: Ia08a57c37a6294e002cb6ce4c0a010c0d2edf973
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/9309
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

util/kconfig/confdata.c

@@ -59,6 +59,7 @@ static void conf_message(const char *fmt, ...)
 	va_start(ap, fmt);
 	if (conf_message_callback)
 		conf_message_callback(fmt, ap);
+	va_end(ap);
 }
 
 const char *conf_get_configname(void)