IB/opa_vnic: Properly return the total MACs in UC MAC list

Do not include EM specified MAC address in total MACs of the
UC MAC list.

Reviewed-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>