broadband-modem: allow querying current charset

So that plugins can use it.

src/mm-broadband-modem.c

@@ -9296,6 +9296,12 @@ mm_broadband_modem_take_and_convert_to_current_charset (MMBroadbandModem *self,
     return mm_utf8_take_and_convert_to_charset (str, self->priv->modem_current_charset);
 }
 
+MMModemCharset
+mm_broadband_modem_get_current_charset (MMBroadbandModem *self)
+{
+    return self->priv->modem_current_charset;
+}
+
 gchar *
 mm_broadband_modem_create_device_identifier (MMBroadbandModem *self,
                                              const gchar *ati,

src/mm-broadband-modem.h

@@ -23,6 +23,7 @@
 
 #include <ModemManager.h>
 
+#include "mm-charsets.h"
 #include "mm-base-modem.h"
 
 #define MM_TYPE_BROADBAND_MODEM            (mm_broadband_modem_get_type ())
@@ -105,6 +106,8 @@ gchar *mm_broadband_modem_take_and_convert_to_utf8 (MMBroadbandModem *self,
 gchar *mm_broadband_modem_take_and_convert_to_current_charset (MMBroadbandModem *self,
                                                                gchar *str);
 
+MMModemCharset mm_broadband_modem_get_current_charset (MMBroadbandModem *self);
+
 /* Create a unique device identifier string using the ATI and ATI1 replies and some
  * additional internal info */
 gchar *mm_broadband_modem_create_device_identifier (MMBroadbandModem *self,