samples: sensor: Add lpcxpresso55s69 to fxos8700 accel-only test

The lpcxpresso55s69 board has an mma8652 accelerometer which is
compatible with the fxos8700 driver in accel-only mode. Now that this
board has an i2c driver, include it in the platform whitelist.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>
1 file changed