docs: Fix groupname for Media API ref docs.
Test: Verified by manually generating docs.

Change-Id: Ia7572db531a9ce28b75f16cd5de115d31d255245
diff --git a/include/ndk/NdkImage.h b/include/ndk/NdkImage.h
index 66005cb..d7443be 100644
--- a/include/ndk/NdkImage.h
+++ b/include/ndk/NdkImage.h
@@ -15,7 +15,7 @@
  */
 
 /**
- * @addtogroup Media Camera
+ * @addtogroup Media
  * @{
  */