ide-disk: set_addressing() fixes

* Return -EIO if arg > 0 and LBA48 is unsupported.

* No need to reset ->addressing.

* Make ->addressing a single bit flag.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 01846f2..65c499a 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -686,14 +686,13 @@
 	if (arg < 0 || arg > 2)
 		return -EINVAL;
 
-	drive->addressing =  0;
-
-	if (drive->hwif->host_flags & IDE_HFLAG_NO_LBA48)
-		return 0;
-
-	if (ata_id_lba48_enabled(drive->id) == 0)
+	if (arg && ((drive->hwif->host_flags & IDE_HFLAG_NO_LBA48) ||
+	    ata_id_lba48_enabled(drive->id) == 0))
 		return -EIO;
 
+	if (arg == 2)
+		arg = 0;
+
 	drive->addressing = arg;
 
 	return 0;