ifconfig: Fix wrong indentation for the status of pfsync(4)

The leading tab is always required, regardless of the configuration of
syncdev or syncpeer, as maxupd, defer and version all require
it.

Reviewed by: kp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D47112

(cherry picked from commit 1c95ec17cae22fb76d4e93c9eada78e03ca1bca6)