dt-bindings: soc: samsung: exynos-sysreg: split from syscon

Split Samsung Exynos SoC SYSREG bindings to own file to narrow the
bindings and do not allow other parts of syscon.yaml.  This allows
further customization of Samsung SoC bindings.

Acked-by: Lee Jones <lee@kernel.org>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Sriranjani P <sriranjani.p@samsung.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20221127123259.20339-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>