Revert "net: maintain namespace isolation between vlan and real device"

Revert "net: maintain namespace isolation between vlan and real device"

[ Upstream commit 59b9997baba5242997ddc7bd96b1391f5275a5a4 ]

This reverts commit 8a83a00b0735190384a348156837918271034144.

It causes regressions for S390 devices, because it does an
unconditional DST drop on SKBs for vlans and the QETH device
needs the neighbour entry hung off the DST for certain things
on transmit.

Arnd can't remember exactly why he even needed this change.

Conflicts:

	drivers/net/macvlan.c
	net/8021q/vlan_dev.c
	net/core/dev.c

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>