fat: fix typo s/supeblock/superblock/

Signed-off-by: Zheng Lv <lv.zheng.2015@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 3bcf579..b902c89 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1589,7 +1589,7 @@
 
 	/*
 	 * GFP_KERNEL is ok here, because while we do hold the
-	 * supeblock lock, memory pressure can't call back into
+	 * superblock lock, memory pressure can't call back into
 	 * the filesystem, since we're only just about to mount
 	 * it and have no inodes etc active!
 	 */