iio: imu: mpu6050: Add support for the ICM 20602 IMU

The Invensense ICM-20602 is a 6-axis MotionTracking device that
combines a 3-axis gyroscope and an 3-axis accelerometer. It is very
similar to the ICM-20608 imu which is already supported by the mpu6050
driver. The main difference is that the ICM-20602 has the i2c bus
disable bit in a separate register.

Signed-off-by: Randolph Maaßen <gaireg@gaireg.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>