Merge branch 'ila-make-identifier-format-optional-and-other-fixes'

Tom Herbert says:

====================
ila: make identifier format optional and other fixes

The identifier type and checksum neutral mapping bits are optional
in identifier formats. This patch set fixes the implementation to
make them optional and configurable.

Specific items:

  - Clean up checksum diff code in ILA
  - Add checksum neutral mapping auto so that checksum neutral
    mapping can be configured without requiring use of the C-bit
  - Add identifier type configuration and allow identifier
    type to be configured so that the identifier type field does
    not need to be present
  - Added ILA documention: ila.txt

I have fixes for ILA in iproute2 that will be poseted separately.

Tested: Ran netperf TCP_RR on various combinations of checksum
mode and the two supported identifier types.

v2:
  - Add proper sign off
  - In ILA LWT, only check prefix length includes identifier type
    if identifier type is enabled (ILA_ATYPE_USE_FORMAT).
  - Add a hook type so that it can be specified whether ILA
    translation is done on input or output route funciton in
    LWT.
====================

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