freedreno/fdperf: Silence a compiler warning about current counter.

It seems like selecting the first here is a fine choice if we can't
find the counter.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7224>

src/freedreno/perfcntrs/fdperf.c

@@ -737,7 +737,7 @@ counter_dialog(void)
 {
 	WINDOW *dialog;
 	struct counter_group *group;
-	int cnt, current = 0, scroll;
+	int cnt = 0, current = 0, scroll;
 
 	/* figure out dialog size: */
 	int dh = h/2;