Use the addrconf_addr_eui48() helper function to set the GUIDs for both
RoCE and iWARP modes, Also make sure the GUIDs are valid EUI-64
identifiers.

Link: https://lore.kernel.org/r/20211107212227.44610-1-kamalheib1@gmail.comSigned-off-by: Kamal Heib <kamalheib1@gmail.com>
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>