Two simple devices. The stk8ba50 datasheet could be found via
google, but I only have the driver for the 8312.

Given they both seem to be 3 axis devices with a single interrupt
line, add them to trivial-devices.yaml
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210401174112.320497-6-jic23@kernel.org