Revert "fs: sync: add missing return if fsync is disabled from userspace."

This reverts commit c9587e60bf202456ff6e8f400b4125f3be3adb30.
Revert "fs: sync: enable fsync by default."

This reverts commit 462470bec338abe06eae0eb068f1e5b7a161de73.
Revert "Added fsync on/off support."

This reverts commit 1a7a089d8280166569caa40cbb7015342a0dd264.