Inside flush_fwd_rx_queues removed redundant prev_tsc update with cur_tsc,
as prev_tsc value is always updated with rte_rdtsc() in for loop.
Coverity issue: 127797
Fixes: f487715f36 ("app/testpmd: add timeout in Rx queue flushing")
Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>