[media] af9013: Fix typo in get_frontend() function

This patch fixes an obvious typo in the get_frontend() function
of the af9013 driver, recently rewritten by Antti Palosaari.
Signed-off-by: Gianluca Gennari <gennarone@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/af9013.c

@@ -880,16 +880,16 @@ static int af9013_get_frontend(struct dvb_frontend *fe)
 
 	switch ((buf[0] >> 2) & 3) {
 	case 0:
-		c->transmission_mode = GUARD_INTERVAL_1_32;
+		c->guard_interval = GUARD_INTERVAL_1_32;
 		break;
 	case 1:
-		c->transmission_mode = GUARD_INTERVAL_1_16;
+		c->guard_interval = GUARD_INTERVAL_1_16;
 		break;
 	case 2:
-		c->transmission_mode = GUARD_INTERVAL_1_8;
+		c->guard_interval = GUARD_INTERVAL_1_8;
 		break;
 	case 3:
-		c->transmission_mode = GUARD_INTERVAL_1_4;
+		c->guard_interval = GUARD_INTERVAL_1_4;
 		break;
 	}