usb: xhci-mtk: check boundary before check tt

check_sch_tt() will access fs_bus_bw[] array, check boundary
firstly to avoid out-of-bounds issue.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1629189389-18779-7-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mtk-sch.c

@@ -600,13 +600,14 @@ static int check_sch_bw(struct mu3h_sch_bw_info *sch_bw,
 	 * and find a microframe where its worst bandwidth is minimum.
 	 */
 	for (offset = 0; offset < sch_ep->esit; offset++) {
-		ret = check_sch_tt(sch_ep, offset);
-		if (ret)
-			continue;
 
 		if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
 			break;
 
+		ret = check_sch_tt(sch_ep, offset);
+		if (ret)
+			continue;
+
 		worst_bw = get_max_bw(sch_bw, sch_ep, offset);
 		if (worst_bw > bw_boundary)
 			continue;