powerpc/spufs: add a missing mutex_unlock

A mutex_unlock(&gang->aff_mutex) in spufs_create_context() is missing
in case spufs_context_open() fails.  As a result, spu_create syscall
and spu_get_idle() may block.

This patch adds the mutex_unlock.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Andre Detsch <adetsch@br.ibm.com>

arch/powerpc/platforms/cell/spufs/inode.c

@@ -496,6 +496,8 @@ spufs_create_context(struct inode *inode, struct dentry *dentry,
 	ret = spufs_context_open(dget(dentry), mntget(mnt));
 	if (ret < 0) {
 		WARN_ON(spufs_rmdir(inode, dentry));
+		if (affinity)
+			mutex_unlock(&gang->aff_mutex);
 		mutex_unlock(&inode->i_mutex);
 		spu_forget(SPUFS_I(dentry->d_inode)->i_ctx);
 		goto out;