dt-bindings:iio:imu:invensense,mpu6050: txt to yaml conversion

dt-bindings:iio:imu:invensense,mpu6050: txt to yaml conversion

As Rob Herring suggested, this no long requires the explicit
i2c-gate binding, but instead just used i2c-controller.yaml
directly.

2 prior examples combinded into one as a single example can show
all of the binding elements as long as the right part is selected.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20201128173343.390165-3-jic23@kernel.org