xfs: fix gcc 4.6 set but not read and unused statement warnings

[hch: dropped a few hunks that need structural changes instead]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_da_btree.c b/fs/xfs/xfs_da_btree.c
index 2adfb76..30fa0e2 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -576,16 +576,14 @@
 	xfs_da_intnode_t *node;
 	xfs_da_node_entry_t *btree;
 	int tmp;
-	xfs_mount_t *mp;
 
 	node = oldblk->bp->data;
-	mp = state->mp;
 	ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
 	ASSERT((oldblk->index >= 0) && (oldblk->index <= be16_to_cpu(node->hdr.count)));
 	ASSERT(newblk->blkno != 0);
 	if (state->args->whichfork == XFS_DATA_FORK)
-		ASSERT(newblk->blkno >= mp->m_dirleafblk &&
-		       newblk->blkno < mp->m_dirfreeblk);
+		ASSERT(newblk->blkno >= state->mp->m_dirleafblk &&
+		       newblk->blkno < state->mp->m_dirfreeblk);
 
 	/*
 	 * We may need to make some room before we insert the new node.