ide: refactor tf_read() method

Simplify tf_read() method, making it deal only with 'struct ide_taskfile' and
the validity flags that the upper layer passes, and factoring out the code that
deals with the high order bytes into ide_tf_readback() to be called from the
only two functions interested, ide_complete_cmd() and ide_dump_sector().

This should stop the needless code duplication in this method and so make
it about twice smaller than it was; along with simplifying the setup for
the method call, this should save both time and space...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 44d7816..7f264ed 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -335,14 +335,11 @@
 
 static u8 ide_read_device(ide_drive_t *drive)
 {
-	struct ide_cmd cmd;
+	struct ide_taskfile tf;
 
-	memset(&cmd, 0, sizeof(cmd));
-	cmd.valid.in.tf = IDE_VALID_DEVICE;
+	drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_DEVICE);
 
-	drive->hwif->tp_ops->tf_read(drive, &cmd);
-
-	return cmd.tf.device;
+	return tf.device;
 }
 
 /**