include: export lapd.h since openBSC needs it

More specifically, the unfinished ericsson rbs2000 BTS.
diff --git a/include/Makefile.am b/include/Makefile.am
index c94d3ee..ea38eec 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -1,3 +1,3 @@
-noinst_HEADERS=mISDNif.h internal.h lapd.h
+noinst_HEADERS=mISDNif.h internal.h
 
 SUBDIRS=osmocom
diff --git a/include/osmocom/abis/Makefile.am b/include/osmocom/abis/Makefile.am
index 85c77b7..ea1eded 100644
--- a/include/osmocom/abis/Makefile.am
+++ b/include/osmocom/abis/Makefile.am
@@ -1,5 +1,6 @@
 osmoabis_HEADERS = abis.h		\
 		   e1_input.h		\
+		   lapd.h		\
 		   logging.h		\
 		   subchan_demux.h	\
 		   ipa_proxy.h		\
diff --git a/include/lapd.h b/include/osmocom/abis/lapd.h
similarity index 100%
rename from include/lapd.h
rename to include/osmocom/abis/lapd.h