Asynchronous Fsync: initial extraction of Async Fsync from HTC

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:

	drivers/mmc/core/mmc.c

Conflicts:
	fs/Kconfig
fs/Kconfig: fix warnings

Signed-off-by: Paul Reioux <reioux@gmail.com>