Added fsync on/off support.

Change-Id: I0328e1a50ec102fa073dbaaea953fe3da7b53077
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
fs: sync: enable fsync by default.

Change-Id: If41dd9ea11c88a702045372826eeb75dfdfb256e
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
fs: sync: add missing return if fsync is disabled from userspace.

Change-Id: Ic64eeb31645cc5367bd6a45e778369c7f523c9d6
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>