Align struct to 32 bytes

Change-Id: I32fd813af7dd2a7d451f5fda278ea888b181fa8e

test/intrapred_test.cc

@@ -209,8 +209,8 @@ class IntraPredBase {
     }
   }
 
-  MACROBLOCKD mb_;
-  MODE_INFO mi_;
+  DECLARE_ALIGNED(32, MACROBLOCKD, mb_);
+  DECLARE_ALIGNED(32, MODE_INFO, mi_);
   uint8_t *data_ptr_[2];  // in the case of Y, only [0] is used
   int stride_;
   int block_size_;