We won't create a full new different modem object based on whether the
ID_MM_FIBOCOM_INITIAL_EPS_OFF_ON tag is found or not. Instead, we
always will create the same object type, and detect whether the OFF/ON
cycle is required during runtime.
When the attach APN settings are changed, the device will go through a
radio on -> radio off -> radio on cycle so that the new changes are
taken into consideration.
This change is done in a Fibocom-specific MBIM modem implementation
because it's working around a firmware bug that would prevent for the
attach settings to be considered automatically.
Back in Linux < 3.6 days, the cdc-wdm ports exposed by the QMI driver
were flagged as owned by the 'usb' subsystem. That changed in 3.6 when
the subsystem was renamed to 'usbmisc':
https://mail.gnome.org/archives/networkmanager-list/2012-June/msg00125.html
This patch removes all monitoring of the 'usb' subsystem completely,
which is anyway a valid subsystem but for which we shouldn't need any
special handling. Right now, with newer kernels, we were using that
monitoring exclusively to get notified of full USB device remove
events, which is really not required as we already process the port
removals one by one.
We simplify the logic everywhere that attempted to match either the
'usb' or 'usbmisc' subsystems, and we no longer require the explicit
checks for the port name being named 'cdc-wdm[0-9]*' in the code, as
that is already taken care of by the ID_MM_CANDIDATE udev tag rule.
