[media] radio-si470x: Lower hardware freq seek signal treshold

The previous value made hardware freq seek not work for me, despite having
good reception of almost all Dutch radio stations.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/si470x/radio-si470x-common.c

@@ -359,7 +359,7 @@ int si470x_start(struct si470x_device *radio)
 
 	/* sysconfig 2 */
 	radio->registers[SYSCONFIG2] =
-		(0x3f  << 8) |				/* SEEKTH */
+		(0x1f  << 8) |				/* SEEKTH */
 		((band  << 6) & SYSCONFIG2_BAND)  |	/* BAND */
 		((space << 4) & SYSCONFIG2_SPACE) |	/* SPACE */
 		15;					/* VOLUME (max) */