crypto: vmx - Increase priority of aes-cbc cipher

BugLink: http://bugs.launchpad.net/bugs/1592481

All of the VMX AES ciphers (AES, AES-CBC and AES-CTR) are set at
priority 1000. Unfortunately this means we never use AES-CBC and
AES-CTR, because the base AES-CBC cipher that is implemented on
top of AES inherits its priority.

To fix this, AES-CBC and AES-CTR have to be a higher priority. Set
them to 2000.

Testing on a POWER8 with:

cryptsetup benchmark --cipher aes --key-size 256

Shows decryption speed increase from 402.4 MB/s to 3069.2 MB/s,
over 7x faster. Thanks to Mike Strosaker for helping me debug
this issue.

Fixes: 8c755ace ("crypto: vmx - Adding CBC routines for VMX module")
Cc: stable@vger.kernel.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit 12d3f49e git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>

drivers/crypto/vmx/aes_cbc.c

@@ -182,7 +182,7 @@ struct crypto_alg p8_aes_cbc_alg = {
 	.cra_name = "cbc(aes)",
 	.cra_driver_name = "p8_aes_cbc",
 	.cra_module = THIS_MODULE,
-	.cra_priority = 1000,
+	.cra_priority = 2000,
 	.cra_type = &crypto_blkcipher_type,
 	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
 	.cra_alignmask = 0,

drivers/crypto/vmx/aes_ctr.c

@@ -166,7 +166,7 @@ struct crypto_alg p8_aes_ctr_alg = {
 	.cra_name = "ctr(aes)",
 	.cra_driver_name = "p8_aes_ctr",
 	.cra_module = THIS_MODULE,
-	.cra_priority = 1000,
+	.cra_priority = 2000,
 	.cra_type = &crypto_blkcipher_type,
 	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
 	.cra_alignmask = 0,