fm10k: wait for queues to drain if stop_hw() fails once

It turns out that sometimes during a reset the Tx queues will be
temporarily stuck longer than .stop_hw() expects. Work around this issue
by attempting to .stop_hw() first. If it tails, wait a number of
attempts until the Tx queues appear to be drained. After this, attempt
stop_hw() again. This ensures that we avoid waiting if we don't need to,
such as during the first initialization of a VF, and give the proper
amount of time necessary to recover from most situations. It is possible
that the hardware is actually stuck. For PFs, this is usually fixed by
a datapath reset. Unfortunately the VF cannot request a similar reset
for itself.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>