crypto: vmx - Adding enable_kernel_vsx() to access VSX instructions

vmx-crypto driver make use of some VSX instructions which are
only available if VSX is enabled. Running in cases where VSX
are not enabled vmx-crypto fails in a VSX exception.

In order to fix this enable_kernel_vsx() was added to turn on
VSX instructions for vmx-crypto.

Signed-off-by: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/crypto/vmx/ghash.c b/drivers/crypto/vmx/ghash.c
index b5e2900..2183a2e 100644
--- a/drivers/crypto/vmx/ghash.c
+++ b/drivers/crypto/vmx/ghash.c
@@ -119,6 +119,7 @@
 	preempt_disable();
 	pagefault_disable();
 	enable_kernel_altivec();
+	enable_kernel_vsx();
 	enable_kernel_fp();
 	gcm_init_p8(ctx->htable, (const u64 *) key);
 	pagefault_enable();
@@ -149,6 +150,7 @@
 			preempt_disable();
 			pagefault_disable();
 			enable_kernel_altivec();
+			enable_kernel_vsx();
 			enable_kernel_fp();
 			gcm_ghash_p8(dctx->shash, ctx->htable,
 				     dctx->buffer, GHASH_DIGEST_SIZE);
@@ -163,6 +165,7 @@
 			preempt_disable();
 			pagefault_disable();
 			enable_kernel_altivec();
+			enable_kernel_vsx();
 			enable_kernel_fp();
 			gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
 			pagefault_enable();
@@ -193,6 +196,7 @@
 			preempt_disable();
 			pagefault_disable();
 			enable_kernel_altivec();
+			enable_kernel_vsx();
 			enable_kernel_fp();
 			gcm_ghash_p8(dctx->shash, ctx->htable,
 				     dctx->buffer, GHASH_DIGEST_SIZE);