Pull request: home: rm unnecessary locking in update; refactor

Merge in DNS/adguard-home from 4499-rm-unnecessary-locking to master

Squashed commit of the following:

commit 6d70472506dd0fd69225454c73d9f7f6a208b76b
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 25 17:26:54 2022 +0300

    home: rm unnecessary locking in update; refactor

scripts/make/go-lint.sh

@@ -136,7 +136,6 @@ underscores() {
 			-e '_freebsd.go'\
 			-e '_linux.go'\
 			-e '_little.go'\
-			-e '_nolinux.go'\
 			-e '_openbsd.go'\
 			-e '_others.go'\
 			-e '_test.go'\