btrfs: kill the key type accessor helpers

btrfs_set_key_type and btrfs_key_type are used inconsistently along with
open coded variants. Other members of btrfs_key are accessed directly
without any helpers anyway.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 340a92d..a7a3863 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1054,7 +1054,7 @@
 		if (key.objectid > device->devid)
 			break;
 
-		if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
+		if (key.type != BTRFS_DEV_EXTENT_KEY)
 			goto next;
 
 		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
@@ -1206,7 +1206,7 @@
 		if (key.objectid > device->devid)
 			break;
 
-		if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
+		if (key.type != BTRFS_DEV_EXTENT_KEY)
 			goto next;
 
 		if (key.offset > search_start) {