backports: backport MPLS support

backports: backport MPLS support

This simply the files that define the structures and
defines used to decode MPLS on the skb. For an example
usage see 960d97f95. The headers were added first via
f3baa393ff.

commit f3baa393ffc9a7aefc0bf767729382085e81f606
Author: Simon Wunderlich <sw@simonwunderlich.de>
Date:   Mon Mar 3 17:23:11 2014 +0100

    UAPI: add MPLS label stack definition

    Labels for the Multiprotocol Label Switching are defined in RFC 3032
    which was superseded by RFC 5462. Add the definition to UAPI and a stub
    header for include/linux.

    Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
    Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
    Signed-off-by: David S. Miller <davem@davemloft.net>
commit 960d97f9518ef6fb8ff87450d6b0c88ce5df9532
Author: Simon Wunderlich <sw@simonwunderlich.de>
Date:   Mon Mar 3 17:23:12 2014 +0100

    cfg80211: add MPLS and 802.21 classification

    MPLS labels may contain traffic control information, which should be
    evaluated and used by the wireless subsystem if present.

    Also check for IEEE 802.21 which is always network control traffic.

    Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
    Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
    Acked-by: Johannes Berg <johannes@sipsolutions.net>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>