fsync: Update fsync control and add reboot notifier

Kanged from:
https://github.com/SlimRoms/kernel_samsung_smdk4412/commit/de3eb6a89ce36a33f2fd1e6e85bd51d35818f2c0

Signed-off-by: cocafe <cocafehj@gmail.com>
Signed-off-by: zwliew <zhaoweiliew@gmail.com>