pinctrl: samsung: add dedicated SoC eint suspend/resume callbacks

pinctrl: samsung: add dedicated SoC eint suspend/resume callbacks

Refactor the existing platform specific suspend/resume callback
so that each SoC variant has it's own callback containing the
SoC specific logic.

This allows exynosautov920 to have a dedicated function for using
eint_con_offset and eint_mask_offset. Also it is easily extendable
for gs101 which will need dedicated logic for handling the varying
register offset of fltcon0 via eint_fltcon_offset.

Reviewed-by: André Draszik <andre.draszik@linaro.org>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20250402-pinctrl-fltcon-suspend-v6-2-78ce0d4eb30c@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>