Merge branch 'mlxsw-spectrum_router-Optimize-LPM-trees'

Jiri Pirko says:

====================
mlxsw: spectrum_router: Optimize LPM trees

Ido says:

This set tries to optimize the structure of the LPM trees used for route
lookup by avoiding lookups that are guaranteed not to return a result.
This is done by making sure only used prefix lengths are present in the
tree.

First two patches are small preparatory steps towards the actual change
in the last patch.
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Signed-off-by: David S. Miller <davem@davemloft.net>