IB/opa-vnic: VNIC Ethernet Management (EM) structure definitions

Define VNIC EM MAD structures and the associated macros. These structures
are used for information exchange between VNIC EM agent (EMA) on the host
and the Ethernet manager. These include the virtual ethernet switch (vesw)
port information, vesw port mac table, summay and error counters,
vesw port interface mac lists and the EMA trap.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Sadanand Warrier <sadanand.warrier@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>