We found the usb-phy lost devices detected ability after continuously
disconnect/connect, this patch add usb2-phy reset/deassert as one part
of previous workaround (commit c1ebf31) to fix it.
Change-Id: Ib7112047eb0f5030406389aa9c8ebd599f8118be
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>