RDMA/ucm: Mark UCM interface as BROKEN

RDMA/ucm: Mark UCM interface as BROKEN

In commit 357d23c811a7 ("Remove the obsolete libibcm library")
in rdma-core [1], we removed obsolete library which used the
/dev/infiniband/ucmX interface.

Following multiple syzkaller reports about non-sanitized
user input in the UCMA module, the short audit reveals the same
issues in UCM module too.

It is better to disable this interface in the kernel,
before syzkaller team invests time and energy to harden
this unused interface.

[1] https://github.com/linux-rdma/rdma-core/pull/279

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>