USB: fix linked-list corruption in rh_call_control()
Using KASAN, Dmitry found a bug in the rh_call_control() routine: If
buffer allocation fails, the routine returns immediately without
unlinking its URB from the control endpoint, eventually leading to
linked-list corruption.
This patch fixes the problem by jumping to the end of the routine
(where the URB is unlinked) when an allocation failure occurs.