hv_netvsc: Fix a warning of suspicious RCU usage

[ Upstream commit 6d0d779d ]

This fixes a warning of "suspicious rcu_dereference_check() usage"
when nload runs.

Fixes: 776e726b

 ("netvsc: fix RCU warning in get_stats")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>