CNB: net: make dev_watchdog() less intrusive

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2073453
Tested: Build, boot and testing using parallel iperf3

dev_watchdog() is used on many NIC to periodically monitor TX queues to detect hangs. Problem is: It stops all queues, then check them, then 'unfreeze' them.

This stops feeding the NIC and also migrates all qdiscs to be serviced on the cpu calling netif_tx_unlock(), causing a potential latency artifact.

Signed-off-by: Ivan Vecera ivecera@redhat.com