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

Make all changes to #include statements and build files.
diff --git a/include/osmocom/rua/RUA_Cause.h b/include/osmocom/rua/RUA_Cause.h
index 63f4007..97a1c1e 100644
--- a/include/osmocom/rua/RUA_Cause.h
+++ b/include/osmocom/rua/RUA_Cause.h
@@ -11,10 +11,10 @@
 #include <asn_application.h>
 
 /* Including external dependencies */
-#include <osmocom/osmo-iuh/rua/RUA_CauseRadioNetwork.h>
-#include <osmocom/osmo-iuh/rua/RUA_CauseTransport.h>
-#include <osmocom/osmo-iuh/rua/RUA_CauseProtocol.h>
-#include <osmocom/osmo-iuh/rua/RUA_CauseMisc.h>
+#include <osmocom/rua/RUA_CauseRadioNetwork.h>
+#include <osmocom/rua/RUA_CauseTransport.h>
+#include <osmocom/rua/RUA_CauseProtocol.h>
+#include <osmocom/rua/RUA_CauseMisc.h>
 #include <constr_CHOICE.h>
 
 #ifdef __cplusplus