mlxsw: spectrum: Increase number of linear entries

The memory region where adjacency entries (nexthops) are stored is
called the KVD linear and is configured during initialization with a
size of 64K.

Extend this area with 32K more entries, that will be partitioned into 64
groups of 0.5K entries, thereby allowing us to support weighted nexthops
with high accuracy.

Change the ratio between both types of hash entries, so as to prevent
reduction in the number of double hash entries, which are used for IPv6
neighbours and routes with a prefix length greater than 64.

Note that the user will be able to control all these sizes once the
devlink resource manager is introduced.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>