rc.d/devmatch: Silence sysctl hw.bus.devctl_nomatch_enabled=1

As with various other rc scripts, we don't want the output from this
being visible in the boot log.

Fixes: 6437872c1d66 ("New sysctl to disable NOMATCH until devmatch runs")
MFC after: 1 week

(cherry picked from commit 62775aebf725a79703592f3276118245a74afdac)