x22x: Fix problem in set allowed mode

NM attempts to set allowed and preferred mode during the connection
process. The plugin x220x does not handle properly when NM request
allowed mode to '2g, 3g' and the preferred mode to 'none'.

This commit attempts to solve the problem described above. When this
situation happens, establish the mode of the modem has 'ANY' (which
seems the safest one) instead of just throwing an error.

Signed-off-by: David Castellanos <dcastellanos@indra.es>

plugins/x22x/mm-broadband-modem-x22x.c

@@ -160,6 +160,8 @@ set_allowed_modes (MMIfaceModem *self,
     else if (allowed == MM_MODEM_MODE_ANY &&
              preferred == MM_MODEM_MODE_NONE)
         syssel = 0;
+    else if (allowed == (MM_MODEM_MODE_2G | MM_MODEM_MODE_3G))
+        syssel = 0;
     else {
         gchar *allowed_str;
         gchar *preferred_str;