CVE-2026-52925 vrf: Fix a potential NPD when removing a port from a VRF

In the Linux kernel, the following vulnerability has been resolved: vrf: Fix a potential NPD when removing a port from a VRF RCU readers that identified a net device as a VRF port using netifisl3slave assume that a subsequent call to netdevmasterupperdevgetrcu will return a VRF device. They then...