usb: xhci: add a member hci_version in xhci_ctrl struct

Add a member to save xHCI version, it's used some times.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/usb/xhci.h

@@ -1227,6 +1227,7 @@ struct xhci_ctrl {
 	struct xhci_scratchpad *scratchpad;
 	struct xhci_virt_device *devs[MAX_HC_SLOTS];
 	int rootdev;
+	u16 hci_version;
 };
 
 unsigned long trb_addr(struct xhci_segment *seg, union xhci_trb *trb);