dt-bindings: arm: rockchip: fix Theobroma-System board bindings

The naming convention for the existing Theobroma boards is
soc-q7module-baseboard, so rk3399-puma-haikou and the in-kernel
devicetrees also follow that scheme.

For some reason in the binding a wrong or outdated naming slipped
in which does not match the used devicetrees and makes the dt-schema
complain now.

Fix this by using the names used in the wild by actual boards.

Fixes: a323a513 ("dt-bindings: arm: Convert Rockchip board/soc bindings to json-schema")
[although the issue was also present in the old txt file]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20190917083453.25744-1-heiko@sntech.de