usb: xhci-mtk: remove unnecessary assignments in periodic TT scheduler

Remove unnecessary variables in check_sch_bw().
No functional changes, just for better readability.

Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20210507021127.54717-3-chunfeng.yun@mediatek.com


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