Merge branch 'add-a-secondary-at-port-to-the-telit-fn990'

Fabio Porcedda says:

====================
Add a secondary AT port to the Telit FN990

In order to add a secondary AT port to the Telit FN990 first add "DUN2"
to mhi_wwan_ctrl.c, after that add a seconday AT port to the
Telit FN990 in pci_generic.c
====================

Link: https://lore.kernel.org/r/20220916144329.243368-1-fabio.porcedda@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>