dt-bindings: iio: imu: add icm20602 bindings to mpu6050

Adding the invensense ICM-20602 to the compatible list of the mpu6050
driver

Signed-off-by: Randolph Maaßen <gaireg@gaireg.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>