NFS: kmalloc() doesn't return an ERR_PTR()

commit 5abc03cd919535c61b813f2319cb38326a41e810 upstream.

Obviously we should check for NULL here instead of IS_ERR().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>