Move overflow detection from mp9250_stop() to
command_query_mpu9250_status(). Currently the host ignores any
contents returned from a stop request, so overflow reporting at that
point has limited utility.
In practice, this change will result in one additional i2c transaction
to the mpu9250 device every 100ms.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>