f2fs: fix description about main_blkaddr node

Don't leave a blank line, to keep the style consistent
with other node descriptions.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -41,8 +41,7 @@ Description:	This parameter controls the number of prefree segments to be
 What:		/sys/fs/f2fs/<disk>/main_blkaddr
 Date:		November 2019
 Contact:	"Ramon Pantin" <pantin@google.com>
-Description:
-		 Shows first block address of MAIN area.
+Description:	Shows first block address of MAIN area.
 
 What:		/sys/fs/f2fs/<disk>/ipu_policy
 Date:		November 2013