CVE-2026-68297 tipc: fix u16 MTU truncation in media and bearer MTU validation

In the Linux kernel, the following vulnerability has been resolved: tipc: fix u16 MTU truncation in media and bearer MTU validation Both TIPCNLMEDIASET and TIPCNLBEARERSET accept user-supplied MTU values but only enforce a minimum bound, not a maximum. When a user sets the MTU to a value exceedin...