Add start_timer_nodelay()

src/include/gpxe/retry.h

 };
 
 extern void start_timer ( struct retry_timer *timer );
+extern void start_timer_nodelay ( struct retry_timer *timer );
 extern void stop_timer ( struct retry_timer *timer );
 
 /**

src/net/retry.c

 	       timer, timer->start, ( timer->start + timer->timeout ) );
 }
 
+/**
+ * Start timer with no delay
+ *
+ * @v timer		Retry timer
+ *
+ * This starts the timer running with a zero timeout value.
+ */
+void start_timer_nodelay ( struct retry_timer *timer ) {
+	start_timer ( timer );
+	timer->timeout = 0;
+}
+
 /**
  * Stop timer
  *