Remove osmo-iuh subdir level from include/ (2/2)

Make all changes to #include statements and build files.
diff --git a/include/osmocom/hnbap/Cause.h b/include/osmocom/hnbap/Cause.h
index 549cc79..1ce4c23 100644
--- a/include/osmocom/hnbap/Cause.h
+++ b/include/osmocom/hnbap/Cause.h
@@ -12,10 +12,10 @@
 #include <asn_application.h>
 
 /* Including external dependencies */
-#include <osmocom/osmo-iuh/hnbap/CauseRadioNetwork.h>
-#include <osmocom/osmo-iuh/hnbap/CauseTransport.h>
-#include <osmocom/osmo-iuh/hnbap/CauseProtocol.h>
-#include <osmocom/osmo-iuh/hnbap/CauseMisc.h>
+#include <osmocom/hnbap/CauseRadioNetwork.h>
+#include <osmocom/hnbap/CauseTransport.h>
+#include <osmocom/hnbap/CauseProtocol.h>
+#include <osmocom/hnbap/CauseMisc.h>
 #include <constr_CHOICE.h>
 
 #ifdef __cplusplus