net: improve queue removal readability in __netif_set_xps_queue

Improve the readability of the loop removing tx-queue from unused
CPUs/rx-queues in __netif_set_xps_queue. The change should only be
cosmetic.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>