ide: use ata_tf_protocols enums

* Add IDE_TFLAG_MULTI_PIO taskfile flag and set it for commands
  using multi-PIO protocol.

* Use ata_tf_protocols enums instead of TASKFILE_* defines to
  denote command's protocol and then rename ->data_phase field
  to ->protocol.

* Remove no longer needed <linux/hdreg.h> includes.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 02128e9..f9decc9 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -298,6 +298,7 @@
 	/* struct ide_cmd was allocated using kmalloc() */
 	IDE_TFLAG_DYN			= (1 << 27),
 	IDE_TFLAG_FS			= (1 << 28),
+	IDE_TFLAG_MULTI_PIO		= (1 << 29),
 };
 
 enum {
@@ -343,7 +344,7 @@
 	};
 	u8			ftf_flags;	/* for TASKFILE ioctl */
 	u32			tf_flags;
-	int			data_phase;
+	int			protocol;
 
 	int			sg_nents;	  /* number of sg entries */
 	int			orig_sg_nents;