usb: mtu3: remove unnecessary pointer checks

The class driver will ensure the parameters are valid
pointers before call the hook function of usb_ep_ops,
so no need check them again.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1595834101-13094-1-git-send-email-chunfeng.yun@mediatek.com


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