ide: add ide_dev_has_iordy() helper (take 4)

* Add ide_dev_has_iordy() helper and use it sl82c105 host driver.

* Remove no longer needed ide_pio_data_t.use_iordy field.

v2/v3:
* Fix issues noticed by Sergei:
  - correct patch description
  - fix comment in ide_get_best_pio_mode()

v4:
* Fix "ata_" prefix (Noticed by Jeff).

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 83a117d..349c22a 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1363,6 +1363,11 @@
 extern int ide_set_xfer_rate(ide_drive_t *drive, u8 rate);
 int ide_use_fast_pio(ide_drive_t *);
 
+static inline int ide_dev_has_iordy(struct hd_driveid *id)
+{
+	return ((id->field_valid & 2) && (id->capability & 8)) ? 1 : 0;
+}
+
 u8 ide_dump_status(ide_drive_t *, const char *, u8);
 
 typedef struct ide_pio_timings_s {
@@ -1374,7 +1379,6 @@
 
 typedef struct ide_pio_data_s {
 	u8 pio_mode;
-	u8 use_iordy;
 	unsigned int cycle_time;
 } ide_pio_data_t;