pf: fix ABI breakage

The introduction of synproxy support changed the size of struct
pf_status, which in turn broke the userspace ABI.

Revert the relevant change. More work is needed on the synproxy code to
keep and expose the counters, but in the mean time this restores the
ABI.

PR: 257469
MFC after: 3 days
Sponsored by: Modirum MDPay