staging: octeon: add missing napi_disable in cvm_oct_rx_shutdown

In the Linux kernel, the following vulnerability has been resolved: staging: octeon: add missing napi_disable in cvm_oct_rx_shutdown cvm_oct_rx_shutdown calls free_irq and netif_napi_del without disabling the napi instance first. As the free_irq only waits for completion of hard interrupt handlers, the napi poll function could still be active. If cvm_oct_remove proceeds to free the plat structure (which holds the NAPI instances), the active poll function will access freed memory, resulting in a use-after-free crash.

Where it's fixed