MAINTAINERS: f2fs: update my email address

Old email address will be invalid after a few days, update it
to kernel.org one.
Signed-off-by: NChao Yu <chao@kernel.org>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

MAINTAINERS

@@ -6903,7 +6903,7 @@ F:	drivers/iommu/exynos-iommu.c
 
 F2FS FILE SYSTEM
 M:	Jaegeuk Kim <jaegeuk@kernel.org>
-M:	Chao Yu <yuchao0@huawei.com>
+M:	Chao Yu <chao@kernel.org>
 L:	linux-f2fs-devel@lists.sourceforge.net
 S:	Maintained
 W:	https://f2fs.wiki.kernel.org/