IB/srpt: Remove struct srpt_node_acl

Since struct srpt_node_acl is identical to struct se_node_acl,
remove the definition of the former structure. This patch does
not change any functionality.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Estrin <alex.estrin@intel.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>