netvsc: don't access netdev->num_rx_queues directly

This structure member is hidden behind CONFIG_SYSFS, and we
get a build error when that is disabled:

drivers/net/hyperv/netvsc_drv.c: In function 'netvsc_set_channels':
drivers/net/hyperv/netvsc_drv.c:754:49: error: 'struct net_device' has no member named 'num_rx_queues'; did you mean 'num_tx_queues'?
drivers/net/hyperv/netvsc_drv.c: In function 'netvsc_set_rxfh':
drivers/net/hyperv/netvsc_drv.c:1181:25: error: 'struct net_device' has no member named 'num_rx_queues'; did you mean 'num_tx_queues'?

As the value is only set once to the argument of alloc_netdev_mq(),
we can compare against that constant directly.

Fixes: ff4a4419 ("netvsc: allow get/set of RSS indirection table")
Fixes: 2b01888d ("netvsc: allow more flexible setting of number of channels")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -776,7 +776,7 @@ static int netvsc_set_channels(struct net_device *net,
 	    channels->rx_count || channels->tx_count || channels->other_count)
 		return -EINVAL;
 
-	if (count > net->num_tx_queues || count > net->num_rx_queues)
+	if (count > net->num_tx_queues || count > VRSS_CHANNEL_MAX)
 		return -EINVAL;
 
 	if (!nvdev || nvdev->destroy)
@@ -1203,7 +1203,7 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
 	rndis_dev = ndev->extension;
 	if (indir) {
 		for (i = 0; i < ITAB_NUM; i++)
-			if (indir[i] >= dev->num_rx_queues)
+			if (indir[i] >= VRSS_CHANNEL_MAX)
 				return -EINVAL;
 
 		for (i = 0; i < ITAB_NUM; i++)