Revert "pNFS: nfs3_set_ds_client should set NFS_CS_NOPING"

This reverts commit c6eb5843.
If a transport is down, then we want to fail over to other transports if
they are listed in the GETDEVICEINFO reply.

Fixes: c6eb5843 ("pNFS: nfs3_set_ds_client should set NFS_CS_NOPING")
Cc: stable@vger.kernel.org # 5.11.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>