voicecall: Rename hfp dialing functions

Calling from memory index is very similar in functionality to dialing
the last called number. So we rename the functions so we can reuse them,
to deal with memory index calling. Function names now also reflect this
is for hfp.

ofono/src/voicecall.c

@@ -1798,7 +1798,7 @@ static DBusMessage *manager_dial(DBusConnection *conn,
 	return __ofono_error_failed(msg);
 }
 
-static void manager_dial_last_callback(const struct ofono_error *error,
+static void manager_dial_hfp_callback(const struct ofono_error *error,
 								void *data)
 {
 	struct ofono_voicecall *vc = data;
@@ -1827,7 +1827,7 @@ static void manager_dial_last_callback(const struct ofono_error *error,
 					__ofono_error_failed(vc->pending));
 }
 
-static int voicecall_dial_last(struct ofono_voicecall *vc,
+static int voicecall_dial_hfp(struct ofono_voicecall *vc,
 					ofono_voicecall_cb_t cb, void *data)
 {
 	struct ofono_modem *modem = __ofono_atom_get_modem(vc->atom);
@@ -1867,7 +1867,7 @@ static DBusMessage *manager_dial_last(DBusConnection *conn,
 
 	vc->pending = dbus_message_ref(msg);
 
-	err = voicecall_dial_last(vc, manager_dial_last_callback, vc);
+	err = voicecall_dial_hfp(vc, manager_dial_hfp_callback, vc);
 
 	if (err >= 0)
 		return NULL;