drivers/crypto/nx: Fixes for multiple races and issues

Fixes a race on driver init with registering algorithms where the
driver status flag wasn't being set before self testing started.

  Added the cra_alignmask field for CBC and ECB modes.

  Fixed a bug in GCM where AES block size was being used instead of
authsize.

  Removed use of blkcipher_walk routines for scatterlist processing.
Corner cases in the code prevent us from processing an entire
scatterlist at a time and walking the buffers in block sized chunks
turns out to be unecessary anyway.

  Fixed off-by-one error in saving off extra data in the sha code.

  Fixed accounting error for number of bytes processed in the sha code.

Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>