modules: camera: add vendor tag functionality

Vendor Tag operations were added in module api v2.2

Change-Id: I352a50759d8bb9389d904bb774659e4be883794b
diff --git a/modules/camera/Metadata.h b/modules/camera/Metadata.h
index 22d2f22..c0d9492 100644
--- a/modules/camera/Metadata.h
+++ b/modules/camera/Metadata.h
@@ -17,6 +17,7 @@
 #ifndef METADATA_H_
 #define METADATA_H_
 
+#include <pthread.h>
 #include <hardware/camera3.h>
 #include <hardware/gralloc.h>
 #include <system/camera_metadata.h>