[XFS] Unwrap xfs_dabuf_global_lock

Un-obfuscate dabuf_global_lock, remove mutex_lock->spin_lock macros, call
spin_lock directly, remove extraneous cookie holdover from old xfs code,
and change lock type to spinlock_t.

SGI-PV: 970382
SGI-Modid: xfs-linux-melb:xfs-kern:29744a

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/xfs_vfsops.c b/fs/xfs/xfs_vfsops.c
index 57be2f7..f90d955 100644
--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -67,7 +67,7 @@
 	extern kmem_zone_t	*xfs_buf_item_zone;
 	extern kmem_zone_t	*xfs_dabuf_zone;
 #ifdef XFS_DABUF_DEBUG
-	extern lock_t	        xfs_dabuf_global_lock;
+	extern spinlock_t        xfs_dabuf_global_lock;
 	spinlock_init(&xfs_dabuf_global_lock, "xfsda");
 #endif