dpif-netdev: Calculate rxq cycles prior to compare_rxq_cycles calls.

dpif-netdev: Calculate rxq cycles prior to compare_rxq_cycles calls.

compare_rxq_cycles sums the latest cycles from each queue for
comparison with each other. While each comparison correctly
gets the latest cycles, the cycles could change between calls
to compare_rxq_cycle. In order to use consistent values through
each call of compare_rxq_cycles, sum the cycles before qsort is
called.

Requested-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>