Use __u8 rather than u8 in SIZE defines exported to userspace.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

--- a/include/linux/hdreg.h
+++ b/include/linux/hdreg.h
@@ -60,13 +60,15 @@
 #define TAG_MASK		0xf8
 #endif /* __KERNEL__ */
 
+#include <linux/types.h>
+
 /*
  * Command Header sizes for IOCTL commands
  */
 
-#define HDIO_DRIVE_CMD_HDR_SIZE		(4 * sizeof(u8))
-#define HDIO_DRIVE_HOB_HDR_SIZE		(8 * sizeof(u8))
-#define HDIO_DRIVE_TASK_HDR_SIZE	(8 * sizeof(u8))
+#define HDIO_DRIVE_CMD_HDR_SIZE		(4 * sizeof(__u8))
+#define HDIO_DRIVE_HOB_HDR_SIZE		(8 * sizeof(__u8))
+#define HDIO_DRIVE_TASK_HDR_SIZE	(8 * sizeof(__u8))
 
 #define IDE_DRIVE_TASK_INVALID		-1
 #define IDE_DRIVE_TASK_NO_DATA		0