leds: simatic-ipc-leds-gpio: Split up into multiple drivers

In order to clearly describe the dependencies between the GPIO
controller drivers and the users the driver is split up into a core,
two drivers and a common header.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230524124628.32295-4-henning.schild@siemens.com