mlx5_{ib,core}: Add query SQ state helper function

Move query SQ state function from mlx5_ib to mlx5_core in order to
have it in shared code.

It will be used in a downstream patch from mlx5e.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>