pinctrl: samsung: add support for exynos7870 pinctrl

Add support for the Exynos7870 SoC pin-controller in the pinctrl driver.
It has 8 GPIO banks, and 3-bit PINCFG_TYPE_DRV width.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Link: https://lore.kernel.org/r/20250301-exynos7870-pinctrl-v3-3-ba1da9d3cd2f@disroot.org


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