OPAL fixups

[Keith Busch]

On Fri, Feb 17, 2017 at 01:59:37PM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> this contains a few more OPAL-related fixups.  It tones down warnings a bit,
> allocates the OPAL-ѕpecific data structure in a separate dynamic allocation,
> checks for support of Security Send/Receive in NVMe before using them,
> and makes sure we re-discovery the security capabilities after each reset.

Patches 1-3 look good to me.