vlan: fix device vlan alias handling

vlan: fix device vlan alias handling

A recent commit changed the vlan chain handling to not treat devices with
non-digit characters after "." as vlan devices. This broke aliases, which
rely on names after the "." component.
Fix dealing with both cases by first trying to set up a vlan regardless
of the non-digit characters, but for the first component allow falling back
to treating the first two parts as a full device name

Fixes: 013a1171e9b0 ("device: do not treat devices with non-digit characters after . as vlan devices")
Signed-off-by: Felix Fietkau <nbd@nbd.name>