MAINTAINERS: add exfat filesystem

Add myself and Sungjong Seo as exfat maintainer.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

MAINTAINERS

@@ -6305,6 +6305,13 @@ F:	include/trace/events/mdio.h
 F:	include/uapi/linux/mdio.h
 F:	include/uapi/linux/mii.h
 
+EXFAT FILE SYSTEM
+M:	Namjae Jeon <namjae.jeon@samsung.com>
+M:	Sungjong Seo <sj1557.seo@samsung.com>
+L:	linux-fsdevel@vger.kernel.org
+S:	Maintained
+F:	fs/exfat/
+
 EXFAT FILE SYSTEM
 M:	Valdis Kletnieks <valdis.kletnieks@vt.edu>
 L:	linux-fsdevel@vger.kernel.org