MAINTAINERS: change reiserfs status to obsolete

Reiserfs file system is no longer supported and is going to be removed
in 2025 as stated in commit eb103a51 ("reiserfs: Deprecate reiserfs").
Signed-off-by: Piotr Siminski <piotr.siminski@globallogic.com>
Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230720115445.15583-1-piotr.siminski@globallogic.com>

MAINTAINERS

@@ -18006,7 +18006,7 @@ F:	include/linux/regmap.h
 
 REISERFS FILE SYSTEM
 L:	reiserfs-devel@vger.kernel.org
-S:	Supported
+S:	Obsolete
 F:	fs/reiserfs/
 
 REMOTE PROCESSOR (REMOTEPROC) SUBSYSTEM