faft: Send send_ctrl_d_to_dut() and send_enter_to_dut() instead

Call the general methods which may support USB keyboard emulator instead.

BUG=chrome-os-partner:11694
TEST=Run firmware_TryFwB/control.dev passed.

Change-Id: I7a71dae6eebdeece6f37005c891476394703a2d1
Reviewed-on: https://gerrit.chromium.org/gerrit/28368
Reviewed-by: Vic Yang <victoryang@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
diff --git a/server/cros/faftsequence.py b/server/cros/faftsequence.py
index d65673a..f596d97 100644
--- a/server/cros/faftsequence.py
+++ b/server/cros/faftsequence.py
@@ -725,11 +725,11 @@
         """
         time.sleep(self.FIRMWARE_SCREEN_DELAY)
         if dev:
-            self.servo.ctrl_d()
+            self.send_ctrl_d_to_dut()
         else:
-            self.servo.enter_key()
+            self.send_enter_to_dut()
         time.sleep(self.FIRMWARE_KEY_DELAY)
-        self.servo.enter_key()
+        self.send_enter_to_dut()
 
 
     def enable_keyboard_dev_mode(self):