crypto: mediatek - Use GCM IV size constant

This patch replace GCM IV size value by their constant name.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/mediatek/mtk-aes.c

@@ -13,6 +13,7 @@
  */
 
 #include <crypto/aes.h>
+#include <crypto/gcm.h>
 #include "mtk-platform.h"
 
 #define AES_QUEUE_SIZE		512
@@ -1103,7 +1104,7 @@ static struct aead_alg aes_gcm_alg = {
 	.decrypt	= mtk_aes_gcm_decrypt,
 	.init		= mtk_aes_gcm_init,
 	.exit		= mtk_aes_gcm_exit,
-	.ivsize		= 12,
+	.ivsize		= GCM_AES_IV_SIZE,
 	.maxauthsize	= AES_BLOCK_SIZE,
 
 	.base = {