octeon_ep: Fix host hang issue during device reboot

In the Linux kernel, the following vulnerability has been resolved: octeon_ep: Fix host hang issue during device reboot When the host loses heartbeat messages from the device, the driver calls the device-specific ndo_stop function, which frees the resources. If the driver is unloaded in this scenario, it calls ndo_stop again, attempting to free resources that have already been freed, leading to a host hang issue. To resolve this, dev_close should be called instead of the device-specific stop function.dev_close internally calls ndo_stop to stop the network interface and performs additional cleanup tasks. During the driver unload process, if the device is already down, ndo_stop is not called.