IB/mlx5: Fix MR registration flow to use UMR properly

[ Upstream commit e5366d309a772fef264ec85e858f9ea46f939848 ]

Driver shouldn't allow to use UMR to register a MR when
umr_modify_atomic_disabled is set. Otherwise it will always end up with a
failure in the post send flow which sets the UMR WQE to modify atomic access
right.

Fixes: c8d75a98 ("IB/mlx5: Respect new UMR capabilities")
Signed-off-by: Guy Levi <guyle@mellanox.com>
Reviewed-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20190731081929.32559-1-leon@kernel.org


Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>