net: rds: rdma_transport.h: delete duplicated word

Delete the doubled word "be" in a comment.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Cc: netdev@vger.kernel.org
Cc: linux-rdma@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>