WPS: Fix wps_validate_credential() argument type

Newer gcc complained about the mismatching len[] argument type. Silence
that by using the correct type.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/wps/wps_validate.c

@@ -1057,7 +1057,7 @@ static int wps_validate_cred(const u8 *cred, size_t len)
 }
 
 
-static int wps_validate_credential(const u8 *cred[], size_t len[], size_t num,
+static int wps_validate_credential(const u8 *cred[], u16 len[], size_t num,
 				   int mandatory)
 {
 	size_t i;