misc: Include abis_rsl.h to remove some compiler warnings
This was introduced by a recent change to gsm_data.h to include
less header files. We really need to access the RSL information
here so it is fine to include the file.
diff --git a/openbsc/src/bsc/osmo_bsc_audio.c b/openbsc/src/bsc/osmo_bsc_audio.c
index 1349263..8db84f9 100644
--- a/openbsc/src/bsc/osmo_bsc_audio.c
+++ b/openbsc/src/bsc/osmo_bsc_audio.c
@@ -23,6 +23,7 @@
#include <openbsc/osmo_msc_data.h>
#include <openbsc/osmo_bsc.h>
+#include <openbsc/abis_rsl.h>
#include <openbsc/gsm_data.h>
#include <openbsc/debug.h>
#include <openbsc/signal.h>