IB/ucm: Fix compiling ucm.c

Even though this interface is marked CONFIG_BROKEN we still expect it to
compile, at least until we delete it completely.

Also mark INFINIBAND_USER_ACCESS_UCM with COMPILE_TEST so these situations
can be detected.

Fixes: e7ff98ae ("RDMA/cma: Constify path record, ib_cm_event, listen_id pointers")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>