[CIFS] Use unsigned ea length for clarity

Jeff correctly noted that using unsigned ea length is more intuitive.
CC: Jeff Lyaton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c

@@ -5392,7 +5392,7 @@ QAllEAsRetry:
 	temp_fea = ea_response_data->list;
 	temp_ptr = (char *)temp_fea;
 	while (list_len > 0) {
-		int name_len;
+		unsigned int name_len;
 		__u16 value_len;
 
 		list_len -= 4;