crypto: sun4i-ss - fix a few signed warning

The variable i is always checked against unsigned value and cannot be
negative.
This patch set it as unsigned.
Signed-off-by: NLABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/sunxi-ss/sun4i-ss-cipher.c

@@ -29,7 +29,8 @@ static int sun4i_ss_opti_poll(struct ablkcipher_request *areq)
 	u32 tx_cnt = 0;
 	u32 spaces;
 	u32 v;
-	int i, err = 0;
+	int err = 0;
+	unsigned int i;
 	unsigned int ileft = areq->nbytes;
 	unsigned int oleft = areq->nbytes;
 	unsigned int todo;
@@ -139,7 +140,8 @@ static int sun4i_ss_cipher_poll(struct ablkcipher_request *areq)
 	u32 tx_cnt = 0;
 	u32 v;
 	u32 spaces;
-	int i, err = 0;
+	int err = 0;
+	unsigned int i;
 	unsigned int ileft = areq->nbytes;
 	unsigned int oleft = areq->nbytes;
 	unsigned int todo;