net/mlx5: E-Switch, Fix drop counters use before creation

First use of drop counters happens in esw_apply_vport_conf function,
while they are allocated later in the flow. Fix that by moving
esw_vport_create_drop_counters function to be called before the first use.

Fixes: b8a0dbe3

 ("net/mlx5e: E-switch, Add steering drop counters")
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>