Include stdlib to fix sim build

Change-Id: I7732461a9351f53f9ddadcfb26485f2e553e056b
diff --git a/media/mtp/mtp.h b/media/mtp/mtp.h
index 7a97d7c..224cfb9 100644
--- a/media/mtp/mtp.h
+++ b/media/mtp/mtp.h
@@ -18,6 +18,7 @@
 #define _MTP_H
 
 #include <stdint.h>
+#include <stdlib.h>
 
 #define MTP_STANDARD_VERSION            100