Reusing mem_get_le{16, 32} defined in vpx_ports/mem_opts.h.

Change-Id: If4b5209ac14aaba6f1c1014bc0497baa8eabfaff
diff --git a/ivfdec.c b/ivfdec.c
index 40394a8..6dcd66f 100644
--- a/ivfdec.c
+++ b/ivfdec.c
@@ -12,6 +12,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "vpx_ports/mem_ops.h"
+
 #include "./ivfdec.h"
 
 static const char *IVF_SIGNATURE = "DKIF";