dt-bindings: reset: sophgo: support SG2042

Add bindings for the reset generator on the SOPHGO SG2042 RISC-V SoC.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Inochi Amaoto <inochiama@outlook.com>
Link: https://lore.kernel.org/r/35c348437b6e18972ccaf90d9c38040caccd1f11.1706577450.git.unicorn_wang@outlook.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>