net: qmi_wwan: Add WeTelecom-WPD600N

The WeTelecom-WPD600N is an LTE module that, in addition to supporting most
"normal" bands, also supports LTE over 450MHz. Manual testing showed that
only interface number three replies to QMI messages.

Cc: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>