vty: show tbf: Drop unneeded check for non-null ms

Since a while a go, a TBF is guaranteed to always have a MS assigned.
Hence, there's no point in checking it.

Change-Id: I89e062432ac671c73731ce68c889aeb5e24277f5
diff --git a/src/pcu_vty_functions.cpp b/src/pcu_vty_functions.cpp
index fb7897d..c2cc950 100644
--- a/src/pcu_vty_functions.cpp
+++ b/src/pcu_vty_functions.cpp
@@ -62,7 +62,7 @@
 		tbf->first_ts,
 		tbf->first_common_ts, tbf->control_ts,
 		tbf->ms_class(),
-		tbf->ms() ? ms_egprs_ms_class(tbf->ms()) : -1,
+		ms_egprs_ms_class(tbf->ms()),
 		VTY_NEWLINE);
 	vty_out(vty, " TS_alloc=");
 	for (int i = 0; i < 8; i++) {