net/mlx4: improve assert control

net/mlx4: improve assert control

Use the MLX4_ASSERT macros instead of the standard assert clause.
Depends on the RTE_LIBRTE_MLX4_DEBUG configuration option to define it.
If RTE_LIBRTE_MLX4_DEBUG is enabled MLX4_ASSERT is equal to RTE_VERIFY
to bypass the global CONFIG_RTE_ENABLE_ASSERT option.
If RTE_LIBRTE_MLX4_DEBUG is disabled, the global CONFIG_RTE_ENABLE_ASSERT
can still make this assert active by calling RTE_VERIFY inside RTE_ASSERT.

Signed-off-by: Alexander Kozyrev <akozyrev@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>