API: add mctp_set_tx_enabled

Provide a method for MCTP bindings to implement flow control

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/libmctp.h b/libmctp.h
index 291b639..8a66ef8 100644
--- a/libmctp.h
+++ b/libmctp.h
@@ -3,6 +3,7 @@
 #ifndef _LIBMCTP_H
 #define _LIBMCTP_H
 
+#include <stdbool.h>
 #include <stdint.h>
 
 typedef uint8_t mctp_eid_t;
@@ -87,6 +88,8 @@
 				struct mctp_pktbuf *pkt);
 };
 
+void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable);
+
 void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt);
 
 /* environment-specific allocation */