Move vlr.h & vlr_sgs.h into osmocom/vlr/

Prepare libvlr to be independent, start by moving the vlr headers
into its own directory.

Change-Id: I8b18b05091b35e744b3234d1ce0d537f56bccf07
diff --git a/include/osmocom/msc/transaction_cc.h b/include/osmocom/msc/transaction_cc.h
index 963cb45..c19c033 100644
--- a/include/osmocom/msc/transaction_cc.h
+++ b/include/osmocom/msc/transaction_cc.h
@@ -28,7 +28,7 @@
 
 #include <osmocom/msc/codec_mapping.h>
 #include <osmocom/msc/transaction.h>
-#include <osmocom/msc/vlr.h>
+#include <osmocom/vlr/vlr.h>
 
 void trans_cc_filter_init(struct gsm_trans *trans);
 void trans_cc_filter_set_ran(struct gsm_trans *trans, enum osmo_rat_type ran_type);