pinctrl: ingenic: add x1600 support

Add support for the Lumissil/Ingenic X1600 SoC.

It uses shadow registers to commit changes to multiple pinctrl
registers in parallel.

Define specific Chip ID, register offsets, pin tables etc.

Handling the unique X1600_GPIO_PU only for the x1600 but
not for x1830 and above must be carefully taken into account.

Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Co-authored-by: Andreas Kemnade <andreas@kemnade.info>
Co-authored-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Paul Boddie <paul@boddie.org.uk>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://lore.kernel.org/84477ec9cb9ed13bf4f6f87d5fb3b55542d31097.1740823241.git.hns@goldelico.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>