ide: ide_id_has_flush_cache_ext() -> ata_id_flush_ext_enabled()

* Add ata_id_flush_ext_enabled() inline helper to <linux/ata.h>.

* ide_id_has_flush_cache_ext() -> ata_id_flush_ext_enabled()

  The latter one also checks if the command is marked as
  supported in word 83 and validity of words 83 & 86.

Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index c159617..ec6664b 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -188,7 +188,7 @@
 			ide_complete_power_step(drive, rq, 0, 0);
 			return ide_stopped;
 		}
-		if (ide_id_has_flush_cache_ext(drive->id))
+		if (ata_id_flush_ext_enabled(drive->id))
 			args->tf.command = ATA_CMD_FLUSH_EXT;
 		else
 			args->tf.command = ATA_CMD_FLUSH;