sfc: add devlink info support for ef100

Add devlink info support for ef100. The information reported is obtained
through the MCDI interface with the specific meaning defined in new
documentation file.

Signed-off-by: Alejandro Lucero <alejandro.lucero-palau@amd.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Acked-by: Martin Habets <habetsm.xilinx@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>