ext4: Remove unnecessary casts of private_data

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8b3b934..84185d2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2219,7 +2219,7 @@
 
 	rc = seq_open(file, &ext4_mb_seq_groups_ops);
 	if (rc == 0) {
-		struct seq_file *m = (struct seq_file *)file->private_data;
+		struct seq_file *m = file->private_data;
 		m->private = sb;
 	}
 	return rc;