Merge branch 'variable-length-ll-headers'

Merge branch 'variable-length-ll-headers'

Willem de Bruijn says:

====================
net: validate variable length ll headers

Allow device-specific validation of link layer headers. Existing
checks drop all packets shorter than hard_header_len. For variable
length protocols, such packets can be valid.

patch 1 adds header_ops.validate and dev_validate_header
patch 2 implements the protocol specific callback for AX25
patch 3 replaces ll_header_truncated with dev_validate_header
====================

Signed-off-by: David S. Miller <davem@davemloft.net>