MCS: move Mode enum outside of class definition

Move Mode (EDGE/GPRS) definition and related functions outside of
GprsCodingScheme class. This allows us to use standard libosmocore
value_string functions.

Change-Id: I3baaac7f1ca3f5b88917a23c1679d63847455f47
diff --git a/src/pcu_vty_functions.cpp b/src/pcu_vty_functions.cpp
index 47a0559..c93935d 100644
--- a/src/pcu_vty_functions.cpp
+++ b/src/pcu_vty_functions.cpp
@@ -79,7 +79,7 @@
 			ul_tbf->window_size(), win->v_q(), win->v_r());
 		vty_out(vty, "%s", VTY_NEWLINE);
 		vty_out(vty, " TBF Statistics:%s", VTY_NEWLINE);
-		if(GprsCodingScheme::GPRS == tbf->ms()->mode()) {
+		if(GPRS == tbf->ms()->mode()) {
 			vty_out_rate_ctr_group(vty, " ", ul_tbf->m_ul_gprs_ctrs);
 		} else {
 			vty_out_rate_ctr_group(vty, " ", ul_tbf->m_ul_egprs_ctrs);
@@ -92,7 +92,7 @@
 			win->window_stalled() ? " STALLED" : "");
 		vty_out(vty, "%s", VTY_NEWLINE);
 		vty_out_rate_ctr_group(vty, " ", tbf->m_ctrs);
-		if(GprsCodingScheme::GPRS == tbf->ms()->mode()) {
+		if(GPRS == tbf->ms()->mode()) {
 			vty_out_rate_ctr_group(vty, " ", dl_tbf->m_dl_gprs_ctrs);
 		} else {
 			vty_out_rate_ctr_group(vty, " ", dl_tbf->m_dl_egprs_ctrs);
@@ -153,8 +153,7 @@
 		VTY_NEWLINE);
 	vty_out(vty, "  Coding scheme downlink: %s%s", mcs_name(ms->current_cs_dl()),
 		VTY_NEWLINE);
-	vty_out(vty, "  Mode:                   %s%s",
-		GprsCodingScheme::modeName(ms->mode()), VTY_NEWLINE);
+	vty_out(vty, "  Mode:                   %s%s", mode_name(ms->mode()), VTY_NEWLINE);
 	vty_out(vty, "  MS class:               %d%s", ms->ms_class(), VTY_NEWLINE);
 	vty_out(vty, "  EGPRS MS class:         %d%s", ms->egprs_ms_class(), VTY_NEWLINE);
 	vty_out(vty, "  PACCH:                  ");