iio: accel: kxcjk-1013: only set power state if CONFIG_PM is defined

When CONFIG_PM is not defined and the driver tries to power off the device,
kxcjk1013_set_power_state will call pm_runtime_put_autosuspend, which is
not implemented (wil return -ENOSYS).

Only call pm_runtime calls to change power state  when CONFIG_PM is defined.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>