dt-bindings: pinctrl: samsung: Document Exynos7885

Document compatible string for Exynos7885 SoC.

Signed-off-by: David Virag <virag.david003@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211031231511.46856-1-virag.david003@gmail.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>