move utils.h functions to libosmocore

This needs the corresponding commit in libosmocore which imports
the related functions
diff --git a/openbsc/src/libcommon/Makefile.am b/openbsc/src/libcommon/Makefile.am
index 84c7544..75f40ee 100644
--- a/openbsc/src/libcommon/Makefile.am
+++ b/openbsc/src/libcommon/Makefile.am
@@ -6,4 +6,4 @@
 
 libcommon_a_SOURCES = bsc_version.c common_vty.c debug.c gsm_data.c \
 		      gsm_data_shared.c socket.c talloc_ctx.c \
-		      gsm_subscriber_base.c utils.c
+		      gsm_subscriber_base.c