usb: dwc3: Fix break from cleanup request loop

If event status says that its last completed TRB but TRB is still owned
by HW then break from the loop, because we are not going to get correct
TRB status from trb control/size register.

Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>