s390/qeth: set static link info during initialization

Hard-code the minimal link info at initialization time, after we
obtained the link_type. qeth_get_link_ksettings() can still override
this with more accurate data from QUERY CARD INFO later on.

Don't set arbitrary defaults for unknown OSA link types, they
certainly won't match any future type.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>