dyndbg: use ESCAPE_SPACE for cat control

`cat control` currently does octal escape, so '\n' becomes "\012".
Change this to display as "\n" instead, which reads much cleaner.

   :#> head -n7 /proc/dynamic_debug/control
   # filename:lineno [module]function flags format
   init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\n"
   init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\n"
   init/main.c:1424 [main]run_init_process =_ "  with arguments:\n"
   init/main.c:1426 [main]run_init_process =_ "    %s\n"
   init/main.c:1427 [main]run_init_process =_ "  with environment:\n"
   init/main.c:1429 [main]run_init_process =_ "    %s\n"
Acked-by: Jason Baron <jbaron@akamai.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220904214134.408619-7-jim.cromie@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/dynamic_debug.c

@@ -900,7 +900,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		   trim_prefix(dp->filename), dp->lineno,
 		   iter->table->mod_name, dp->function,
 		   ddebug_describe_flags(dp->flags, &flags));
-	seq_escape(m, dp->format, "\t\r\n\"");
+	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
 	seq_puts(m, "\"\n");
 
 	return 0;