dt-bindings: display/msm/gpu: define reg-names in top-level

dt-bindings: display/msm/gpu: define reg-names in top-level

All devices should (and actually do) have same order of entries, if
possible.  That's the case for reg/reg-names, so define the reg-names in
top-level to enforce that.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/600510/
Link: https://lore.kernel.org/r/20240623-qcom-adreno-dts-bindings-driver-v2-2-9496410de992@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>