iio:kxcjk-1013: Add support for SMO8500 device

The Onda v975w tablet contains an accelerometer that's advertised over
ACPI as SMO8500. This device is however a KXCJ9 accelerometer as
can be seen in the Windows driver's INF file, and from the etching on
the chipset ("KXCJ9 41566 0414").

This patch also removes the attempt to get the IRQ for the "data ready"
signal, as it does not seem to be supported by this device on this
platform.

Signed-off-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>