channel: Make channel_matches_target_addr_for_extend() static

It isn't used outside channel.c.

Part of 33817.

src/core/or/channel.c

@@ -83,6 +83,11 @@
 
 #include "core/or/cell_queue_st.h"
 
+/* Static function prototypes */
+
+static int channel_matches_target_addr_for_extend(channel_t *chan,
+                                                  const tor_addr_t *target);
+
 /* Global lists of channels */
 
 /* All channel_t instances */

src/core/or/channel.h

@@ -737,8 +737,6 @@ int channel_is_outgoing(channel_t *chan);
 void channel_mark_client(channel_t *chan);
 void channel_clear_client(channel_t *chan);
 int channel_matches_extend_info(channel_t *chan, extend_info_t *extend_info);
-int channel_matches_target_addr_for_extend(channel_t *chan,
-                                           const tor_addr_t *target);
 unsigned int channel_num_circuits(channel_t *chan);
 MOCK_DECL(void,channel_set_circid_type,(channel_t *chan,
                                         crypto_pk_t *identity_rcvd,