samples: sensor: bq274xx: Fix platform whitelist

The sensor is on the nrf9160_innblue22 not nrf9160_innblue21.  This
causes CI build failures since there is no dts node for the sensor
on the nrf9160_innblue21 board.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
1 file changed