[media] e4000: implement PLL lock v4l control

Implement PLL lock control to get PLL lock flag status from tuner
synthesizer.

Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/tuners/e4000_priv.h

@@ -30,6 +30,7 @@ struct e4000_priv {
 	u32 clock;
 	struct dvb_frontend *fe;
 	struct v4l2_subdev sd;
+	bool active;
 
 	/* Controls */
 	struct v4l2_ctrl_handler hdl;
@@ -41,6 +42,7 @@ struct e4000_priv {
 	struct v4l2_ctrl *mixer_gain;
 	struct v4l2_ctrl *if_gain_auto;
 	struct v4l2_ctrl *if_gain;
+	struct v4l2_ctrl *pll_lock;
 };
 
 struct e4000_pll {