uml: UML net driver does not allow for vlans

See ancient discussion at
http://marc.info/?l=user-mode-linux-devel&m=101990155831279&w=2

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=7854

Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Roland Kletzing <devzero@web.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/include/shared/net_user.h

@@ -8,7 +8,7 @@
 
 #define ETH_ADDR_LEN (6)
 #define ETH_HEADER_ETHERTAP (16)
-#define ETH_HEADER_OTHER (14)
+#define ETH_HEADER_OTHER (26) /* 14 for ethernet + VLAN + MPLS for crazy people */
 #define ETH_MAX_PACKET (1500)
 
 #define UML_NET_VERSION (4)