[PATCH net-next] vlan: Mark expected switch fall-through

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

net/8021q/vlan_dev.c: In function ‘vlan_dev_ioctl’:
net/8021q/vlan_dev.c:374:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (!net_eq(dev_net(dev), &init_net))
      ^
net/8021q/vlan_dev.c:376:2: note: here
  case SIOCGMIIPHY:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 net/8021q/vlan_dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 2a9a60733594..c546c4228075 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -373,6 +373,7 @@ static int vlan_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	case SIOCSHWTSTAMP:
 		if (!net_eq(dev_net(dev), &init_net))
 			break;
+		/* fall through */
 	case SIOCGMIIPHY:
 	case SIOCGMIIREG:
 	case SIOCSMIIREG:
-- 
2.21.0