MAINTAINERS: exfat: add myself as reviewer

I have been contributing to exfat for sometime and I would like to help
with code reviews as well.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

Author: YuezhangMo

MAINTAINERS

@@ -8415,6 +8415,7 @@ N:	binfmt
 EXFAT FILE SYSTEM
 M:	Namjae Jeon <linkinjeon@kernel.org>
 M:	Sungjong Seo <sj1557.seo@samsung.com>
+R:	Yuezhang Mo <yuezhang.mo@sony.com>
 L:	linux-fsdevel@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat.git