usb: xhci: add quirks flag to support MediaTek xHCI 0.96

There some vendor quirks for MTK xHCI 0.96 host controller:
1. It defines some extra SW scheduling parameters for HW
   to minimize the scheduling effort for synchronous and
   interrupt endpoints. The parameters are put into reserved
   DWs of slot context and endpoint context.
2. Its TDS in  Normal TRB defines a number of packets that
   remains to be transferred for a TD after processing all
   Max packets in all previous TRBs.

Tested-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index 8ff7185..f3f181d 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -258,6 +258,7 @@
 	if (ret)
 		goto ssusb_init_err;
 
+	mtk->ctrl.quirks = XHCI_MTK_HOST;
 	hcor = (struct xhci_hcor *)((uintptr_t)mtk->hcd +
 			HC_LENGTH(xhci_readl(&mtk->hcd->cr_capbase)));