crypto: img-hash - fix some compile warnings

GCC complains about that %u is the wrong format string for size_t and
also that "ret" is unused.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/img-hash.c

@@ -192,7 +192,7 @@ static int img_hash_xmit_cpu(struct img_hash_dev *hdev, const u8 *buf,
 	u32 count, len32;
 	const u32 *buffer = (const u32 *)buf;
 
-	dev_dbg(hdev->dev, "xmit_cpu:  length: %u bytes\n", length);
+	dev_dbg(hdev->dev, "xmit_cpu:  length: %zu bytes\n", length);
 
 	if (final)
 		hdev->flags |= DRIVER_FLAGS_FINAL;
@@ -459,7 +459,6 @@ static int img_hash_hw_init(struct img_hash_dev *hdev)
 {
 	unsigned long long nbits;
 	u32 u, l;
-	int ret;
 
 	img_hash_write(hdev, CR_RESET, CR_RESET_SET);
 	img_hash_write(hdev, CR_RESET, CR_RESET_UNSET);