Add caution to USB device (#649)

* Add caution to USB device

Signed-off-by: Jack Yu <jack.yu@suse.com>

* Revise sentence

Co-authored-by: Jillian <67180770+jillian-maroket@users.noreply.github.com>

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Signed-off-by: Jack Yu <jack.yu@suse.com>
Co-authored-by: Jillian <67180770+jillian-maroket@users.noreply.github.com>

docs/advanced/addons/pcidevices.md

@@ -104,6 +104,10 @@ A `USBDevice` resource in Harvester represents a USB device on the node. USB dev
 
 USB passthrough is slightly different from PCI passthrough. For example, you can fully control a USB controller with four USB ports by creating a `PCIDeviceClaim`. However, you can also create a `USBDeviceClaim` to control only one USB port. The other three USB ports remain available to the node.
 
+:::caution
+Before you remove the USB device, detach it from the virtual machine and then disable passthrough on the **USB Devices** screen.
+:::
+
 ### Enable Passthrough on a USB Device
 
 1. On the Harvester UI, go to **Advanced** > **USB Devices**.