Instead of deleting unsupported providers after building, patch
CMakeLists.txt to not build them at all.
libcxgb3 and libnes do not exist anymore in rdma-core.
ib_qib is not built in the RHEL kernel (CONFIG_INFINIBAND_QIB is not
set), so modprobe config for truescale is unneeded.
Resolves: rhbz#2112984, rhbz#2142687
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>