crypto: caam - Pad SG length when allocating hash edesc

Because hardware will read in multiples of 4 SG entries, ensure
the allocated length is always padded.  This was already done
by some callers of ahash_edesc_alloc, but ahash_digest was conspicuously
missing.

In any case, doing it in the allocation function ensures that the
memory is always there.

Reported-by: Guangwu Zhang <guazhang@redhat.com>
Fixes: a5e5c13398 ("crypto: caam - fix S/G table passing page boundary")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamhash.c

@@ -708,6 +708,7 @@ static struct ahash_edesc *ahash_edesc_alloc(struct ahash_request *req,
 		       GFP_KERNEL : GFP_ATOMIC;
 	struct ahash_edesc *edesc;
 
+	sg_num = pad_sg_nents(sg_num);
 	edesc = kzalloc(struct_size(edesc, sec4_sg, sg_num), flags);
 	if (!edesc)
 		return NULL;