For older hosts without multi-channel (vRSS) support, and some error
cases, we still need to set the real number of queues to one.
This patch adds this missing setting.

Fixes: 8195b139 ("hv_netvsc: fix deadlock on hotplug")
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>