RDMA/cma: Simplify DEVICE_REMOVAL for internal_id

RDMA/cma: Simplify DEVICE_REMOVAL for internal_id

cma_process_remove() triggers an unconditional rdma_destroy_id() for
internal_id's and skips the event deliver and transition through
RDMA_CM_DEVICE_REMOVAL.

This is confusing and unnecessary. internal_id always has
cma_listen_handler() as the handler, have it catch the
RDMA_CM_DEVICE_REMOVAL event and directly consume it and signal removal.

This way the FSM sequence never skips the DEVICE_REMOVAL case and the
logic in this hard to test area is simplified.

Link: https://lore.kernel.org/r/20200723070707.1771101-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>