media: dvb_frontend: be sure to init dvb_frontend_handle_ioctl() return code

As smatch warned:
	drivers/media/dvb-core/dvb_frontend.c:2468 dvb_frontend_handle_ioctl() error: uninitialized symbol 'err'.

The ioctl handler actually got a regression here: before changeset
d73dcf0cdb95 ("media: dvb_frontend: cleanup ioctl handling logic"),
the code used to return -EOPNOTSUPP if an ioctl handler was not
implemented on a driver. After the change, it may return a random
value.

Fixes: d73dcf0cdb95 ("media: dvb_frontend: cleanup ioctl handling logic")

Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Tested-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-core/dvb_frontend.c

@@ -2110,7 +2110,7 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 	struct dvb_frontend *fe = dvbdev->priv;
 	struct dvb_frontend_private *fepriv = fe->frontend_priv;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
-	int i, err;
+	int i, err = -EOPNOTSUPP;
 
 	dev_dbg(fe->dvb->device, "%s:\n", __func__);
 
@@ -2145,6 +2145,7 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 			}
 		}
 		kfree(tvp);
+		err = 0;
 		break;
 	}
 	case FE_GET_PROPERTY: {
@@ -2196,6 +2197,7 @@ static int dvb_frontend_handle_ioctl(struct file *file,
 			return -EFAULT;
 		}
 		kfree(tvp);
+		err = 0;
 		break;
 	}