crypto: caam - do not register AES-XTS mode on LP units

When using AES-XTS on a Wandboard, we receive a Mode error:
caam_jr 2102000.jr1: 20001311: CCB: desc idx 19: AES: Mode error.

According to the Security Reference Manual, the Low Power AES units
of the i.MX6 do not support the XTS mode. Therefore we must not
register XTS implementations in the Crypto API.

Signed-off-by: Sven Ebenfeld <sven.ebenfeld@gmail.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>

Cc: <stable@vger.kernel.org> # 4.4+
Fixes: c6415a6016 "crypto: caam - add support for acipher xts(aes)"
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamalg.c

@@ -4583,6 +4583,15 @@ static int __init caam_algapi_init(void)
 		if (!aes_inst && (alg_sel == OP_ALG_ALGSEL_AES))
 				continue;
 
+		/*
+		 * Check support for AES modes not available
+		 * on LP devices.
+		 */
+		if ((cha_vid & CHA_ID_LS_AES_MASK) == CHA_ID_LS_AES_LP)
+			if ((alg->class1_alg_type & OP_ALG_AAI_MASK) ==
+			     OP_ALG_AAI_XTS)
+				continue;
+
 		t_alg = caam_alg_alloc(alg);
 		if (IS_ERR(t_alg)) {
 			err = PTR_ERR(t_alg);