libgb: remove dependencies to openbsc/vty.h and openbsc/gsm_data.h

Rather than using openbsc internal data/functions, we now use only
internal and libosmocore-provided ones.
diff --git a/openbsc/src/libgb/Makefile.am b/openbsc/src/libgb/Makefile.am
index fc1847f..eafbc34 100644
--- a/openbsc/src/libgb/Makefile.am
+++ b/openbsc/src/libgb/Makefile.am
@@ -5,5 +5,5 @@
 noinst_LIBRARIES = libgb.a
 
 libgb_a_SOURCES = gprs_ns.c gprs_ns_frgre.c gprs_ns_vty.c \
-		  gprs_bssgp.c gprs_bssgp_util.c gprs_bssgp_vty.c gprs_bssgp_bss.c
-#gprs_llc.c gprs_llc_vty.c crc24.c
+		  gprs_bssgp.c gprs_bssgp_util.c gprs_bssgp_vty.c \
+		  gprs_bssgp_bss.c common_vty.c