crypto: sun8i-ss - fix infinite loop in sun8i_ss_setup_ivs()

There is no i decrement in while (i >= 0) loop.

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 359e893e ("crypto: sun8i-ss - rework handling of IV")
Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c

@@ -170,6 +170,7 @@ static int sun8i_ss_setup_ivs(struct skcipher_request *areq)
 	while (i >= 0) {
 		dma_unmap_single(ss->dev, rctx->p_iv[i], ivsize, DMA_TO_DEVICE);
 		memzero_explicit(sf->iv[i], ivsize);
+		i--;
 	}
 	return err;
 }