net: libwx: Fix dead code for duplicate check

Fix duplicate check on polling timeout.

Fixes: 1efa9bfe ("net: libwx: Implement interaction with firmware")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>