Due to the old method has already been marked as deprecated in binding
doc, so obviously it's better to update the example to new bindings
as well.

Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Leonard Crestez <leonard.crestez@nxp.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>