iio: imu: mpu6050: add missing available scan masks

Driver only supports 3-axis gyro and/or 3-axis accel.
For icm20602, temp data is mandatory for all configurations.

Fix all single and double axis configurations (almost never used) and more
importantly fix 3-axis gyro and 6-axis accel+gyro buffer on icm20602 when
temp data is not enabled.

Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Fixes: 1615fe41

 ("iio: imu: mpu6050: Fix FIFO layout for ICM20602")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>