IB/core: Change rdma_protocol_iboe to roce

After discussion upstream, it was agreed to transition the usage of iboe
in the kernel to roce.  This keeps our terminology consistent with what
was finalized in the IBTA Annex 16 and IBTA Annex 17 publications.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>