Ignoring deprecated register only in flex.

Change-Id: If1aa41c3e04c7e4e7b98056568cd3d3890c188ef
diff --git a/hidl-gen_l.ll b/hidl-gen_l.ll
index 578ec47..431ea12 100644
--- a/hidl-gen_l.ll
+++ b/hidl-gen_l.ll
@@ -58,6 +58,7 @@
 
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-parameter"
+#pragma clang diagnostic ignored "-Wdeprecated-register"
 
 %}