sim-mbim: increase the timeout for the MBIM_CID_HOME_PROVIDER query

Increase the timeout from 10 seconds to 30 seconds when reading the
operator information through the MBIM_CID_HOME_PROVIDER query.
We have observed cases where it took more than 12 seconds on a Fibocom
L850-GL modem with specific China Unicom SIMs.

This timeout was actually the cause of a corruption of the operator name
(e.g. returning '@' rather than the real operator name) on the Intel
XMM7360 based L850-GL. The following scenario was happening:
- the base-sim code sends a first MBIM 'home-provider' query to read the
  operator identifier.
- this query times-out after 10 seconds.
- the base-sim immediately sends another MBIM 'home-provider' query to
  read the operator name.
- the modem returns a corrupted operator identifier.
Intel helped for the debugging and indicates that when the first query
happens, the modem starts reading the SIM files (EF SPN/PNN), apparently
it's taking a long time, when it's receives the second query while the
first one is not entirely processed, this triggers a bug (in the modem
firmware) and returns a corrupted name.

src/mm-sim-mbim.c

@@ -274,7 +274,7 @@ load_operator_identifier (MMBaseSim *self,
     message = mbim_message_home_provider_query_new (NULL);
     mbim_device_command (device,
                          message,
-                         10,
+                         30,
                          NULL,
                          (GAsyncReadyCallback)load_operator_identifier_ready,
                          task);
@@ -335,7 +335,7 @@ load_operator_name (MMBaseSim *self,
     message = mbim_message_home_provider_query_new (NULL);
     mbim_device_command (device,
                          message,
-                         10,
+                         30,
                          NULL,
                          (GAsyncReadyCallback)load_operator_name_ready,
                          task);