ide: include <linux/hdreg.h> only when needed

* Include <linux/ata.h> directly in <linux/ide.h>
  instead of through <linux/hdreg.h>.

* Include <linux/hdreg.h> only when needed.

Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index eeb2c3b..6e1a25e 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -31,6 +31,7 @@
 #include <linux/mutex.h>
 #include <linux/leds.h>
 #include <linux/ide.h>
+#include <linux/hdreg.h>
 
 #include <asm/byteorder.h>
 #include <asm/irq.h>