net: wwan: hwsim: refactor to support more port types

net: wwan: hwsim: refactor to support more port types

Just introduced WWAN NMEA port type needs a testing option. The WWAN HW
simulator was developed with the AT port type in mind and cannot be
easily extended. Refactor it now to make it capable to support more port
types.

No big functional changes, mostly renaming with a little code
rearrangement.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260126062158.308598-7-slark_xiao@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>