[media] adv7180: fix querystd() method for no input signal

When the input signal is not detected querystd() method should return
V4L2_STD_UNKNOWN instead of previously latched analog video standard.

Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/i2c/adv7180.c

@@ -135,6 +135,10 @@ struct adv7180_state {
 
 static v4l2_std_id adv7180_std_to_v4l2(u8 status1)
 {
+	/* in case V4L2_IN_ST_NO_SIGNAL */
+	if (!(status1 & ADV7180_STATUS1_IN_LOCK))
+		return V4L2_STD_UNKNOWN;
+
 	switch (status1 & ADV7180_STATUS1_AUTOD_MASK) {
 	case ADV7180_STATUS1_AUTOD_NTSM_M_J:
 		return V4L2_STD_NTSC;