charts: add full MO and MT voice call diagram

Add voice_call_full.msc, generated from a real 2G<->3G voice call log fed to
msc_log_to_ladder.py.

The idea is to document how the voice call sequence of events changes in
upcoming patches.

Change-Id: I8a907d6a4ece1f3ad78da75a8c3e3e76afd5418d
diff --git a/doc/sequence_charts/Makefile.am b/doc/sequence_charts/Makefile.am
index f1775c8..6782f44 100644
--- a/doc/sequence_charts/Makefile.am
+++ b/doc/sequence_charts/Makefile.am
@@ -13,18 +13,20 @@
 	inter_bsc_ho.png \
 	inter_msc_ho.png \
 	mncc_call_fsm.png \
+	voice_call_full.png \
 	$(NULL)
 
 msc: \
 	$(builddir)/mncc_call_fsm.png \
 	$(builddir)/inter_bsc_ho.png \
 	$(builddir)/inter_msc_ho.png \
+	$(builddir)/voice_call_full.png \
 	$(NULL)
 
 dot: \
 	$(NULL)
 
-$(builddir)/%.png: $(srcdir)/%.msc
+$(builddir)/%.png: %.msc
 	mscgen -T png -o $@ $<
 
 $(builddir)/%.png: $(srcdir)/%.dot