IB/mlx5: Fix alternate path code

Userspace flag IBV_QP_ALT_PATH is supposed to set the alternate path
including fields alt_pkey_index and alt_timeout.
Added IB_QP_PKEY_INDEX and IB_QP_TIMEOUT to the attribute mask when
calling mlx5_set_path for the alternate path to force setting the
alt_pkey_index and alt_timeout values.

Fixes: bf24481a3a7c4 ('IB/mlx5: Consider alternate path in pkey ...')
Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Reviewed-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>