Merge branch 'mlxsw-spectrum_router-Add-GRE-tunnel-support-for-Spectrum-2'

Ido Schimmel says:

====================
mlxsw: spectrum_router: Add GRE tunnel support for Spectrum-2

Nir says:

In Spectrum-2, HW implementation of layer 3 tunnels differs from
Spectrum-1 when it comes to the underlay routing table selection.
Spectrum-2 uses a dedicated RIF that points to the virtual router used
for forwarding the encapsulated packets, while Spectrum-1 explicitly
specifies the virtual router itself.

Patches #1 and #2 add additional fields in RITR - Router interface table
register and RTDP - Routing tunnel decap properties respectively, the
fields are required for the new underlay RIF needed for Spectrum-2.

Patches #3-4 allow different set of RIF operations per ASIC type. The
first patch splits the operations and the following patch sets RIF ops
according to ASIC type.

Patches #5-9 introduce small changes to existing code to allow existence
of a dedicated underlay RIF along with the underlay virtual router, and
to support that new type of RIF that has no device.

Patch #10 takes care of updating the tunnel decap properties egress
underlay RIF required for Spectrum-2.

Patch #11 adds the implementation of Spectrum-2 specific RIF operations
and essentially enables layer 3 GRE tunnels on Spectrum-2.

Finally patches #12-18 add tests for GRE IP-in-IP tunnels, both in flat
and hierarchical topologies.
====================

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