dt-bindings: Drop Li Yang as maintainer for all bindings

dt-bindings: Drop Li Yang as maintainer for all bindings

Remove Li Yang from all device tree bindings because mails to this
address are bouncing.

Commit fbdd90334a62 ("MAINTAINERS: Drop Li Yang as their email address
stopped working") already removed the entry from the MAINTAINERS but
didn't address all the in-file entries of the device tree bindings.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>