Add a new config option INFINIBAND_USER_MAD to control whether we
build ib_umad.  Change INFINIBAND_USER_VERBS to INFINIBAND_USER_ACCESS,
and have it control ib_ucm and ib_uat as well as ib_uverbs.
Signed-off-by: James Lentini <jlentini@netapp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>