ide: add IDE_DFLAG_NIEN_QUIRK device flag

Add IDE_DFLAG_NIEN_QUIRK device flag and use it instead of
drive->quirk_list.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 9654bd3..243cf65 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -488,11 +488,15 @@
 
 		if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 		    hwif != prev_port) {
+			ide_drive_t *cur_dev =
+				prev_port ? prev_port->cur_dev : NULL;
+
 			/*
 			 * set nIEN for previous port, drives in the
-			 * quirk_list may not like intr setups/cleanups
+			 * quirk list may not like intr setups/cleanups
 			 */
-			if (prev_port && prev_port->cur_dev->quirk_list == 0)
+			if (cur_dev &&
+			    (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
 				prev_port->tp_ops->write_devctl(prev_port,
 								ATA_NIEN |
 								ATA_DEVCTL_OBS);