IB/mlx5: Fix XRC QP support after introducing extended atomic

IB/mlx5: Fix XRC QP support after introducing extended atomic

Extended atomics are supported with RC and XRC QP types, but the commit
citied in the Fixes line added an unneeded check to
to_mlx5_access_flags. This broke XRC QPs.

The following ib_atomic_bw invocation over XRC reproduces the issue:
   ib_atomic_bw -d mlx5_1 --connection=XRC --atomic_type=FETCH_AND_ADD

It is safe to remove such checks because the QP type was already checked
in ib_modify_qp_is_ok(), which was previously called from
mlx5_ib_modify_qp.

Fixes: 5b20122c415b ("IB/mlx5: Add support for extended atomic operations")
Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>