libstagefrighthw: Remove padding in encoder_nativehandle_buffer_type

Padding is no longer needed as native handle is directly passed without
involving shared memory in framework, and the handle pointer size will
not cause invalid access while passing handle in a 64 bit process.

Change-Id: I184542e7deb816ac2cb97e39a16c5e4fe83c1eb6
diff --git a/libstagefrighthw/QComOMXMetadata.h b/libstagefrighthw/QComOMXMetadata.h
index b37a38f..545ce56 100644
--- a/libstagefrighthw/QComOMXMetadata.h
+++ b/libstagefrighthw/QComOMXMetadata.h
@@ -26,10 +26,7 @@
 #ifdef USE_NATIVE_HANDLE_SOURCE
     typedef struct encoder_nativehandle_buffer_type {
         MetadataBufferType buffer_type;
-        union {
-            buffer_handle_t meta_handle;
-            uint64_t padding;
-        };
+        buffer_handle_t meta_handle;
     } encoder_nativehandle_buffer_type;
 #endif