qede: Don't expose self-test for VFs

PFs and VFs differ in their registered ethtool operations,
but they're using a common function for get_sset_count().
As a result, `ethtool -i' for a VF would indicate it supports
selftest, although that's not the case.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>