iio:imu:inv_mpu6050: Use regmap_noinc_read for fifo reads.

We should not be assuming that we are reading a sequence of
registers as here we are doing a read of a lot of data from
a single register address.

Not marked for stable as by coincidence it being wrong doesn't
make any difference.

Suggested-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Link: https://lore.kernel.org/r/20200722155103.979802-19-jic23@kernel.org