STiH415/6 SoC support is being removed from the kernel.
This patch updates the sti dt powerdown bindings and
removes references to these obsolete platforms.
Signed-off-by: NPeter Griffin <peter.griffin@linaro.org>
Cc: <p.zabel@pengutronix.de>
Cc: <robh+dt@kernel.org>
Acked-by: NRob Herring <robh@kernel.org>