crypto: nx - Fix reentrancy bugs

This patch fixes a host of reentrancy bugs in the nx driver.  The
following algorithms are affected:

* CCM
* GCM
* CTR
* XCBC
* SHA256
* SHA512

The crypto API allows a single transform to be used by multiple
threads simultaneously.  For example, IPsec will use a single tfm
to process packets for a given SA.  As packets may arrive on
multiple CPUs that tfm must be reentrant.

The nx driver does try to deal with this by using a spin lock.
Unfortunately only the basic AES/CBC/ECB algorithms do this in
the correct way.

The symptom of these bugs may range from the generation of incorrect
output to memory corruption.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>