Move out gbproxy to its own subdir

Change-Id: I2cc98d3a276d953609bbbbaa9782a0112687791e
diff --git a/tests/gbproxy/Makefile.am b/tests/gbproxy/Makefile.am
index ef38fb6..cb245b4 100644
--- a/tests/gbproxy/Makefile.am
+++ b/tests/gbproxy/Makefile.am
@@ -32,10 +32,10 @@
 	$(NULL)
 
 gbproxy_test_LDADD = \
-	$(top_builddir)/src/gprs/gb_proxy.o \
-	$(top_builddir)/src/gprs/gb_proxy_patch.o \
-	$(top_builddir)/src/gprs/gb_proxy_peer.o \
-	$(top_builddir)/src/gprs/gb_proxy_tlli.o \
+	$(top_builddir)/src/gbproxy/gb_proxy.o \
+	$(top_builddir)/src/gbproxy/gb_proxy_patch.o \
+	$(top_builddir)/src/gbproxy/gb_proxy_peer.o \
+	$(top_builddir)/src/gbproxy/gb_proxy_tlli.o \
 	$(top_builddir)/src/gprs/gprs_gb_parse.o \
 	$(top_builddir)/src/gprs/gprs_llc_parse.o \
 	$(top_builddir)/src/gprs/crc24.o \