net/mlx5: add trunk dynamic grow for indexed pool

net/mlx5: add trunk dynamic grow for indexed pool

This commit add trunk dynamic grow for the indexed pool.

In case for pools which are not sure the entry number needed, pools can
be configured in increase progressively mode. It means the trunk size
will be increased dynamically one after one, then reach a stable value.
It saves memory to avoid allocate a very big trunk at beginning.

User should set both the grow_shift and grow_trunk to help the trunk
grow works. Keep one or both grow_shift and grow_trunk as 0 makes the
trunk work as fixed size.

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>