There is no need to require LOCAL_DMA_LKEY support as the
PD allocation makes sure that there is a local_dma_lkey. Also
correctly set a return value in error path.

This caused a NULL pointer dereference in mlx5 which removed
the support for LOCAL_DMA_LKEY.

Fixes: bb6c96d7 ("xprtrdma: Replace global lkey with lkey local to PD")
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>