kernel: Fix kernel regression in local-broadcast routes

kernel: Fix kernel regression in local-broadcast routes

Backport a patch from upstream kernel 6.17-rc4 which fixes a regression
introduced in the latest stable kernel versions.

This is already in the Linus stable queues for the next minor kernel
updates.

Fixes: 1c92e468d544 ("kernel: bump 6.6 to 6.6.103")
Fixes: f39c7e103f9a ("kernel: bump 6.12 to 6.12.43")
Reported-by: Goetz Goerisch <[email protected]>
Signed-off-by: Hauke Mehrtens <[email protected]>
(cherry picked from commit c589fb7bafae01c55adc8e3111e7763cc18b82f2)