staging: iio: adt7316: fix register and bit definitions

Change two register addresses and one bit definition to match the
datasheet.

Note that there are many issues in this driver so I would
not suggest backporting these fixes to stable trees.

Signed-off-by: Jeremy Fertic <jeremyfertic@gmail.com>
Fixes: 35f6b6b8 ("staging: iio: new ADT7316/7/8 and ADT7516/7/9 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>