compat_ioctl: move drivers to compat_ptr_ioctl

Each of these drivers has a copy of the same trivial helper function to
convert the pointer argument and then call the native ioctl handler.

We now have a generic implementation of that, so use it.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/usb/core/devio.c

@@ -2685,18 +2685,6 @@ static long usbdev_ioctl(struct file *file, unsigned int cmd,
 	return ret;
 }
 
-#ifdef CONFIG_COMPAT
-static long usbdev_compat_ioctl(struct file *file, unsigned int cmd,
-			unsigned long arg)
-{
-	int ret;
-
-	ret = usbdev_do_ioctl(file, cmd, compat_ptr(arg));
-
-	return ret;
-}
-#endif
-
 /* No kernel lock - fine */
 static __poll_t usbdev_poll(struct file *file,
 				struct poll_table_struct *wait)
@@ -2720,9 +2708,7 @@ const struct file_operations usbdev_file_operations = {
 	.read =		  usbdev_read,
 	.poll =		  usbdev_poll,
 	.unlocked_ioctl = usbdev_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl =   usbdev_compat_ioctl,
-#endif
+	.compat_ioctl =   compat_ptr_ioctl,
 	.mmap =           usbdev_mmap,
 	.open =		  usbdev_open,
 	.release =	  usbdev_release,