net: Fix a bug in removing queues from XPS map

While removing queues from the XPS map, the individual CPU ID
alone was used to index the CPUs map, this should be changed to also
factor in the traffic class mapping for the CPU-to-queue lookup.

Fixes: 184c449f ("net: Add support for XPS with QoS via traffic classes")
Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>