V4L/DVB (13396): correct initialization of audio_mode

This initialization of the value of audio_mode is the one used if nothing
matches in the subsequent switch.  The variable audio_mode is subsequently
assigned to constants such as TUNER_AUDIO_MONO and TUNER_AUDIO_STEREO.
TUNER_AUDIO_STEREO has the same value as V4L2_TUNER_MODE_STEREO, so it
would seem better to use that value here.
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/saa717x.c

@@ -1312,7 +1312,7 @@ static int saa717x_s_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *vt)
 		"MONO", "STEREO", "LANG1", "LANG2/SAP"
 	};
 
-	audio_mode = V4L2_TUNER_MODE_STEREO;
+	audio_mode = TUNER_AUDIO_STEREO;
 
 	switch (vt->audmode) {
 		case V4L2_TUNER_MODE_MONO: