bsc: Move gsm_subscriber_base.c to libcommon

Since it is planned to use struct gsm_subscriber to manage subscriber
data in the SGSN, this file which contains the generic subscriber
related methods is moved to libcommon.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/libcommon/Makefile.am b/openbsc/src/libcommon/Makefile.am
index e41326f..75f40ee 100644
--- a/openbsc/src/libcommon/Makefile.am
+++ b/openbsc/src/libcommon/Makefile.am
@@ -4,4 +4,6 @@
 
 noinst_LIBRARIES = libcommon.a
 
-libcommon_a_SOURCES = bsc_version.c common_vty.c debug.c gsm_data.c gsm_data_shared.c socket.c talloc_ctx.c
+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