CVE-2026-43173 net: ethernet: xscale: Check for PTP support properly

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: xscale: Check for PTP support properly In ixp4xxgettsinfo ixp46xptpfind is called unconditionally despite this feature only existing on ixp46x, leading to the following splat from tcpdump: root@OpenWrt: tcpdump -vv...