[misc] Fix the make distcheck

Mention the two new header files, do not list isdnsync twice
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index d28c803..9c8fa7b 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -1,7 +1,7 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
 AM_CFLAGS=-Wall
 
-sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config isdnsync \
+sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config \
                 isdnsync bsc_mgcp
 noinst_LIBRARIES = libbsc.a libmsc.a libvty.a libsccp.a
 noinst_HEADERS = vty/cardshell.h