eax: Use uint64_t member of nettle_block16.

ChangeLog

+2019-07-08  Niels Möller  <nisse@lysator.liu.se>
+
+	* eax.c (block16_xor): Use uint64_t member of nettle_block16.
+
 2019-07-02  Niels Möller  <nisse@lysator.liu.se>
 
 	From Dmitry Eremin-Solenikov:

eax.c

@@ -54,12 +54,8 @@ omac_init (union nettle_block16 *state, unsigned t)
 static void
 block16_xor (union nettle_block16 *dst, const union nettle_block16 *src)
 {
-  dst->w[0] ^= src->w[0];
-  dst->w[1] ^= src->w[1];
-#if SIZEOF_LONG == 4
-  dst->w[2] ^= src->w[2];
-  dst->w[3] ^= src->w[3];
-#endif
+  dst->u64[0] ^= src->u64[0];
+  dst->u64[1] ^= src->u64[1];
 }
 
 static void