Btrfs: compat code fixes

The btrfs git kernel trees is used to build a standalone tree for
compiling against older kernels.  This commit makes the standalone tree
work with 2.6.27

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/compat.h b/fs/btrfs/compat.h
index dd1defd..75e4426 100644
--- a/fs/btrfs/compat.h
+++ b/fs/btrfs/compat.h
@@ -25,6 +25,7 @@
 # define  __pagevec_lru_add_file __pagevec_lru_add
 # define open_bdev_exclusive open_bdev_excl
 # define close_bdev_exclusive(bdev, mode) close_bdev_excl(bdev)
+typedef unsigned __bitwise__ fmode_t;
 #endif