hw/rdma: Delete unused headers inclusion

This is a trivial cleanup patch.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Kamal Heib <kheib@redhat.com>
Message-Id: <20190505105112.22691-1-yuval.shaia@oracle.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>