[VLAN]: Add two missing checks to vlan_ioctl_handler()
In vlan_ioctl_handler() the code misses couple checks for
error return values.
Signed-off-by: Mika Kukkonen <mikukkon@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
authored by Mika Kukkonen and committed by David S. Miller 7eb1b3d3 0d77d59f