MDEV-24600 fixup: Remove unused trx_register_for_2pc()

storage/innobase/handler/ha_innodb.cc

@@ -2384,18 +2384,6 @@ trx_is_registered_for_2pc(
 	return(trx->is_registered == 1);
 }
 
-/*********************************************************************//**
-Note that a transaction has been registered with MySQL 2PC coordinator. */
-static inline
-void
-trx_register_for_2pc(
-/*==================*/
-	trx_t*	trx)	/* in: transaction */
-{
-	trx->is_registered = 1;
-	ut_ad(!trx->active_commit_ordered);
-}
-
 /*********************************************************************//**
 Note that a transaction has been deregistered. */
 static inline