[media] af9013: Don't accept invalid bandwidth

commit d7b76c91 upstream.

If userspace sends an invalid bandwidth, it should either return
EINVAL or switch to auto mode.

This driver will go past an array and program the hardware on a
wrong way if this happens.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/media/dvb-frontends/af9013.c

@@ -606,6 +606,10 @@ static int af9013_set_frontend(struct dvb_frontend *fe)
 			}
 		}
 
+		/* Return an error if can't find bandwidth or the right clock */
+		if (i == ARRAY_SIZE(coeff_lut))
+			return -EINVAL;
+
 		ret = af9013_wr_regs(state, 0xae00, coeff_lut[i].val,
 			sizeof(coeff_lut[i].val));
 	}