Loxigen: added src/dst meta id matches

Encode a 1 byte src and 1 byte dst 'meta' ID into
ofp_match's pad2 byte.
diff --git a/c_gen/templates/loci_show.h b/c_gen/templates/loci_show.h
index a28a7d4..1a1f80f 100644
--- a/c_gen/templates/loci_show.h
+++ b/c_gen/templates/loci_show.h
@@ -332,6 +332,8 @@
 #define LOCI_SHOW_u32_ipv4_netmask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_u8_l2_table_enable(writer, cookie, val) LOCI_SHOW_u8(writer, cookie, val)
 #define LOCI_SHOW_u16_l2_table_priority(writer, cookie, val) LOCI_SHOW_u16(writer, cookie, val)
+#define LOCI_SHOW_u8_src_meta_id(writer, cookie, val) LOCI_SHOW_u8(writer, cookie, val)
+#define LOCI_SHOW_u8_dst_meta_id(writer, cookie, val) LOCI_SHOW_u8(writer, cookie, val)