MDEV-29475 trx_undo_rseg_free() does not write redo log

trx_undo_rseg_free(): Revert an inadvertent change that was done
as part of the merge a42c80bd

storage/innobase/trx/trx0undo.cc

@@ -822,9 +822,8 @@ static void trx_undo_seg_free(const trx_undo_t *undo)
 			buf_block_t* rseg_header = trx_rsegf_get(
 				rseg->space, rseg->page_no, &mtr);
 			compile_time_assert(FIL_NULL == 0xffffffff);
-			memset(TRX_RSEG + TRX_RSEG_UNDO_SLOTS
-			       + undo->id * TRX_RSEG_SLOT_SIZE +
-			       rseg_header->frame, 0xff, 4);
+			mtr.memset(rseg_header, TRX_RSEG + TRX_RSEG_UNDO_SLOTS
+				   + undo->id * TRX_RSEG_SLOT_SIZE, 4, 0xff);
 			MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_USED);
 		}