md: change type of first arg to sync_page_io.

Currently sync_page_io takes a 'bdev'.
Every caller passes 'rdev->bdev'.
We will soon want another field out of the rdev in sync_page_io,
So just pass the rdev instead of the bdev out of it.

Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0b6fa2a..3149bf3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -721,8 +721,8 @@
 	complete((struct completion*)bio->bi_private);
 }
 
-int sync_page_io(struct block_device *bdev, sector_t sector, int size,
-		   struct page *page, int rw)
+int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
+		 struct page *page, int rw)
 {
 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
 	struct completion event;
@@ -730,7 +730,7 @@
 
 	rw |= REQ_SYNC | REQ_UNPLUG;
 
-	bio->bi_bdev = bdev;
+	bio->bi_bdev = rdev->bdev;
 	bio->bi_sector = sector;
 	bio_add_page(bio, page, size, 0);
 	init_completion(&event);
@@ -756,7 +756,7 @@
 		return 0;
 
 
-	if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
+	if (!sync_page_io(rdev, rdev->sb_start, size, rdev->sb_page, READ))
 		goto fail;
 	rdev->sb_loaded = 1;
 	return 0;