Also rename it to cm_remove_remote(). This function now removes the
tracking of the remote ID/QPN in the redblack trees from a cm_id_private.

Replace a open-coded version with a call. The open coded version was
deleting only the remote_id, however at this call site the qpn can not
have been in the RB tree either, so the cm_remove_remote() will do the
same.

Link: https://lore.kernel.org/r/20200506074701.9775-6-leon@kernel.orgSigned-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>