Revert "switch do_fsync() to fget_light()"

This reverts commit af67c2f8731ed92ad679f7d522fef7e1a66ee06b.
Revert "Added FSync Control version 1 (thanks Ezekeel)"

This reverts commit d08934a03c109c8cc3718e1482021a0787ac8736.
Added fsync on/off support.

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
fs: sync: enable fsync by default.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
fs: sync: add missing return if fsync is disabled from userspace.

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>