usb: usbtmc: Fix memory leak in usbtmc_ioctl_request

Kernel memory is allocated twice in new function
usbtmc_ioctl_request and creates a memory leak.
This fix removes the superfluous kmalloc().
Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Fixes: 658f24f4 ("usb: usbtmc: Add ioctl for generic requests on control")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -1895,10 +1895,6 @@ static int usbtmc_ioctl_request(struct usbtmc_device_data *data,
 	if (res)
 		return -EFAULT;
 
-	buffer = kmalloc(request.req.wLength, GFP_KERNEL);
-	if (!buffer)
-		return -ENOMEM;
-
 	if (request.req.wLength > USBTMC_BUFSIZE)
 		return -EMSGSIZE;