simtech: disable CMER/CIND support explicitly

The logic to setup the generic +CIND indications in the SIM7600E seems
to end up breaking connectivity when in TTY+PPP mode. If we issue the
AT+CMER=3,0,0,1 command, this will end up in the modem not replying a
correct CONNECT response to the ATD command.

Let's disable these +CIND indications completely in the simtech
plugin, as there is even no AT command reference saying those are
supported.

Fixes https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/144

plugins/simtech/mm-broadband-modem-qmi-simtech.c

@@ -52,6 +52,7 @@ mm_broadband_modem_qmi_simtech_new (const gchar  *device,
                          MM_BASE_MODEM_PLUGIN,     plugin,
                          MM_BASE_MODEM_VENDOR_ID,  vendor_id,
                          MM_BASE_MODEM_PRODUCT_ID, product_id,
+                         MM_BROADBAND_MODEM_INDICATORS_DISABLED, TRUE,
                          NULL);
 }
 

plugins/simtech/mm-broadband-modem-simtech.c

@@ -826,6 +826,7 @@ mm_broadband_modem_simtech_new (const gchar *device,
                          MM_BASE_MODEM_PLUGIN, plugin,
                          MM_BASE_MODEM_VENDOR_ID, vendor_id,
                          MM_BASE_MODEM_PRODUCT_ID, product_id,
+                         MM_BROADBAND_MODEM_INDICATORS_DISABLED, TRUE,
                          NULL);
 }