usb: class: usbtmc.c: Cleaning up uninitialized variables

There is a risk that the variable will be used without being initialized.

This was largely found by using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -715,7 +715,7 @@ static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
 	u8 *buffer;
 	int rv;
 	int n;
-	int actual;
+	int actual = 0;
 	int max_size;
 
 	dev = &data->intf->dev;