f2fs: fix typo

Fix typo and some grammatical errors.

The words "filesystem" and "readahead" are being used without the space treewide.

Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index a5950db..06e1679 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -527,7 +527,7 @@
 		int free;
 		/*
 		 * If value is NULL, it is remove operation.
-		 * In case of update operation, we caculate free.
+		 * In case of update operation, we calculate free.
 		 */
 		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
 		if (found)