multiq: requeue should rewind the current_band

Currently dequeueing a packet and requeueing the same packet will cause a
different packet to be pulled on the next dequeue.  This change forces
requeue to rewind the current_band.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>