usb: xhci-mtk: remove unnecessary members of mu3h_sch_tt struct

The members @usb_tt and @tt_port in mu3h_sch_tt struct
are not used after initialization, so can be removed

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/9afecc2411895a3c76658df26ebca1c961a39fbb.1615170625.git.chunfeng.yun@mediatek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>