usb: usbtmc: uninitialized symbol 'actual' in usbtmc_ioctl_clear

Fix uninitialized symbol 'actual' in function usbtmc_ioctl_clear.

When symbol 'actual' is not initialized and usb_bulk_msg() fails,
the subsequent kernel debug message shows a random value.
Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Fixes: dfee02ac ("usb: usbtmc: Fix ioctl USBTMC_IOCTL_CLEAR")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -1679,6 +1679,7 @@ static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
 		do {
 			dev_dbg(dev, "Reading from bulk in EP\n");
 
+			actual = 0;
 			rv = usb_bulk_msg(data->usb_dev,
 					  usb_rcvbulkpipe(data->usb_dev,
 							  data->bulk_in),