input: sensors: disable batching for gyro on mpu6050.

Max FIFO count should reflect the exact number of samples which can be
buffered but mpu6050 has 1024 byte common FIFO for accel and gyro.
So disable batching for gyro to use the FIFO for buffering accel samples.

Change-Id: I45f4a941c182ce8ec0955b1efc1ac73a957311d6
Signed-off-by: Kiran Raparthy <krapar@codeaurora.org>