crypto: mediatek - Use IPAD/OPAD constant

This patch simply replace all occurrence of HMAC IPAD/OPAD value by their
define.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/mediatek/mtk-sha.c

@@ -12,6 +12,7 @@
  * Some ideas are from atmel-sha.c and omap-sham.c drivers.
  */
 
+#include <crypto/hmac.h>
 #include <crypto/sha.h>
 #include "mtk-platform.h"
 
@@ -825,8 +826,8 @@ static int mtk_sha_setkey(struct crypto_ahash *tfm, const u8 *key,
 	memcpy(bctx->opad, bctx->ipad, bs);
 
 	for (i = 0; i < bs; i++) {
-		bctx->ipad[i] ^= 0x36;
-		bctx->opad[i] ^= 0x5c;
+		bctx->ipad[i] ^= HMAC_IPAD_VALUE;
+		bctx->opad[i] ^= HMAC_OPAD_VALUE;
 	}
 
 	return 0;