mgcp_endp: make wildcarded detection separate

osmo-mgw currently does only a very simple detection method for
wildcarded requests, but it makes sense to split this detection
off into a separate function so that it can be used from different code
locations and we still have it at one place only.

Change-Id: I27018c01afb8acabfcf5d435c996cc9806e52d6b
Related: SYS#5535
diff --git a/include/osmocom/mgcp/mgcp_endp.h b/include/osmocom/mgcp/mgcp_endp.h
index 8d19b44..db1a897 100644
--- a/include/osmocom/mgcp/mgcp_endp.h
+++ b/include/osmocom/mgcp/mgcp_endp.h
@@ -134,6 +134,7 @@
 void mgcp_endp_release(struct mgcp_endpoint *endp);
 int mgcp_endp_claim(struct mgcp_endpoint *endp, const char *callid);
 void mgcp_endp_update(struct mgcp_endpoint *endp);
+bool mgcp_endp_is_wildcarded(const char *epname);
 struct mgcp_endpoint *mgcp_endp_by_name_trunk(int *cause, const char *epname,
 					      const struct mgcp_trunk *trunk);
 struct mgcp_endpoint *mgcp_endp_by_name(int *cause, const char *epname,