rspro_util: Add rspro_IpAddr2str() to get stringified version of IpAddr_t

Change-Id: Ic6cccb00d1d65bdab84178acb1e0525e11bc1315
diff --git a/src/rspro_util.h b/src/rspro_util.h
index 7a0c8ed..26b3883 100644
--- a/src/rspro_util.h
+++ b/src/rspro_util.h
@@ -38,3 +38,4 @@
 				     const uint8_t *tpdu, unsigned int tpdu_len);
 
 void rspro_comp_id_retrieve(struct app_comp_id *out, const ComponentIdentity_t *in);
+const char *rspro_IpAddr2str(const IpAddress_t *in);