iio: accel: kxcjk1013: Add rudimentary regulator support

kxcjk1013 devices have VDD and VDDIO power lines. Need
to make sure the regulators are enabled before any
communication with kxcjk1013. This patch introduces
vdd/vddio regulators for kxcjk1013.

Signed-off-by: Devajith V S <devajithvs@gmail.com>
Link: https://lore.kernel.org/r/20201213172437.2779-2-devajithvs@gmail.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>