cnn.h: fix include guard

Change-Id: Ie6024c7eb1c6b5e0afd82e8760753ab509b5fb8f
diff --git a/av1/encoder/cnn.h b/av1/encoder/cnn.h
index 1a6c03a4c..850c326 100644
--- a/av1/encoder/cnn.h
+++ b/av1/encoder/cnn.h
@@ -9,8 +9,8 @@
  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  */
 
-#ifndef AOM_AV1_COMMON_CNN_H_
-#define AOM_AV1_COMMON_CNN_H_
+#ifndef AOM_AV1_ENCODER_CNN_H_
+#define AOM_AV1_ENCODER_CNN_H_
 
 #ifdef __cplusplus
 extern "C" {
@@ -200,4 +200,4 @@
 }  // extern "C"
 #endif
 
-#endif  // AOM_AV1_COMMON_CNN_H_
+#endif  // AOM_AV1_ENCODER_CNN_H_