Convert ext4 to use unlocked_ioctl

I checked ext4_ioctl and it looked largely safe to not be used
without BKL.  So convert it over to unlocked_ioctl.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index ac35ec5..20507a2 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -129,7 +129,7 @@
 	.write		= do_sync_write,
 	.aio_read	= generic_file_aio_read,
 	.aio_write	= ext4_file_write,
-	.ioctl		= ext4_ioctl,
+	.unlocked_ioctl = ext4_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= ext4_compat_ioctl,
 #endif