crypto: lrw - use correct alignmask

Commit c778f96b ("crypto: lrw - Optimize tweak computation")
incorrectly reduced the alignmask of LRW instances from
'__alignof__(u64) - 1' to '__alignof__(__be32) - 1'.

However, xor_tweak() and setkey() assume that the data and key,
respectively, are aligned to 'be128', which has u64 alignment.

Fix the alignmask to be at least '__alignof__(be128) - 1'.

Fixes: c778f96b ("crypto: lrw - Optimize tweak computation")
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/lrw.c

@@ -388,7 +388,7 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb)
 	inst->alg.base.cra_priority = alg->base.cra_priority;
 	inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
-				       (__alignof__(__be32) - 1);
+				       (__alignof__(be128) - 1);
 
 	inst->alg.ivsize = LRW_BLOCK_SIZE;
 	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +