Minor refactoring for fabric.p4

Change-Id: I736b20fc95b4a03afa1074eb777a23507530b44f
diff --git a/pipelines/fabric/src/main/resources/include/header.p4 b/pipelines/fabric/src/main/resources/include/header.p4
index 3b153be..df9958b 100644
--- a/pipelines/fabric/src/main/resources/include/header.p4
+++ b/pipelines/fabric/src/main/resources/include/header.p4
@@ -22,11 +22,13 @@
 @controller_header("packet_in")
 header packet_in_header_t {
     port_num_t ingress_port;
+    bit<7> _pad;
 }
 
 @controller_header("packet_out")
 header packet_out_header_t {
     port_num_t egress_port;
+    bit<7> _pad;
 }
 
 header ethernet_t {
@@ -121,6 +123,7 @@
     bit<8> ip_proto;
     bit<16> l4_src_port;
     bit<16> l4_dst_port;
+    bit<16> original_ether_type;
 }
 
 struct parsed_headers_t {