Adds support for jumbo frame selftest. Works only for mtu size greater than 1500. Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com> Link: https://patch.msgid.link/20251031111555.774425-5-Raju.Rangoju@amd.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>