Merge branch '6lowpan'

Alexander Aring says:

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This patch series cleanup the 6LoWPAN header creation and extend the use
of skb_*_header functions.

Patch 2/4 fix issues of parsing the mac header. The ieee802.15.4 header
has a dynamic size which depends on frame control bits. This patch replaces the
static mac header len calculation with a dynamic one.
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Signed-off-by: David S. Miller <davem@davemloft.net>