edge: Show current mode in VTY

Add the current mode to the output of the 'show ms imsi' and
'show ms tlli' commands.

Sponsored-by: On-Waves ehf
diff --git a/src/gprs_coding_scheme.h b/src/gprs_coding_scheme.h
index d1fc064..f02ca51 100644
--- a/src/gprs_coding_scheme.h
+++ b/src/gprs_coding_scheme.h
@@ -87,6 +87,7 @@
 	static GprsCodingScheme getGprsByNum(unsigned num);
 	static GprsCodingScheme getEgprsByNum(unsigned num);
 
+	static const char *modeName(Mode mode);
 private:
 	enum Scheme m_scheme;
 };