Supports buffering, IIO events and changing sampling frequency.

Datasheet available at:
http://www.semtech.com/images/datasheet/sx9500_ag.pdfSigned-off-by: NVlad Dogaru <vlad.dogaru@intel.com>
Reviewed-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>