openflow_input: use of_ prefix in input files

No change to generated code.
diff --git a/openflow_input/bsn_l2_table b/openflow_input/bsn_l2_table
index 2a54b71..d5135d0 100644
--- a/openflow_input/bsn_l2_table
+++ b/openflow_input/bsn_l2_table
@@ -28,7 +28,7 @@
 #version 1
 
 // BSN L2 table configuration messages
-struct ofp_bsn_set_l2_table {
+struct of_bsn_set_l2_table {
     uint8_t version;
     uint8_t type;
     uint16_t length;
@@ -41,7 +41,7 @@
     uint8_t[4] pad;
 };
 
-struct ofp_bsn_get_l2_table_request {
+struct of_bsn_get_l2_table_request {
     uint8_t version;
     uint8_t type;
     uint16_t length;
@@ -50,7 +50,7 @@
     uint32_t subtype;   // BSN_L2_TABLE_GET_REQUEST
 };
 
-struct ofp_bsn_get_l2_table_reply {
+struct of_bsn_get_l2_table_reply {
     uint8_t version;
     uint8_t type;
     uint16_t length;