IB/mlx5: Replace numerical constant with predefined MACRO

Replace the pre-defined macro signifying inline umr instead
of the numerical constant.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>