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/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c
index 4953028..7701427 100644
--- a/drivers/ide/ide-ioctls.c
+++ b/drivers/ide/ide-ioctls.c
@@ -148,7 +148,7 @@
 			       IDE_TFLAG_IN_NSECT;
 	}
 	tf->command = args[0];
-	cmd.data_phase = args[3] ? TASKFILE_IN : TASKFILE_NO_DATA;
+	cmd.protocol = args[3] ? ATA_PROT_PIO : ATA_PROT_NODATA;
 
 	if (args[3]) {
 		cmd.tf_flags |= IDE_TFLAG_IO_16BIT;