gpio-f7188x: Add support for NCT5104D

The Nuvoton NCT5104D is a Super I/O with four UARTs and 17 GPIO lines,
found on PC Engines APU2 boards. Like the NCT6126D, it keeps its GPIOs
in logical device 7, uses 1 for input in the direction register, and
has a single data register and no Fintek vendor ID.

It differs from the NCT6126D in three ways:
- the device ID carries the silicon revision in its low nibble, so
  match 0xC452 (rev. B) and 0xC453 (rev. C); the NCT6102D and NCT6106D
  report the same IDs and are untested
- the output type sits in logical device 0x0F, one register per group,
  with 1 for open drain
- GP0x and GP1x share their pins with UART C and UART D (CR1C bits 3
  and 2). Register a bank only when its pins are routed to GPIO and its
  group is enabled in LD7 CR30, and log each skipped bank

Only GP0x and GP1x are supported; GP67, the one line of group 6, is
left out: its pin is not connected on the APU2.

This replaces the out-of-tree gpio-nct5104d driver that PC Engines
ships with the datasheet, which was posted once in 2017:
https://github.com/tasanakorn/linux-gpio-nct5104d
https://lore.kernel.org/r/77f71974-541e-7e06-d37d-c52b9623ed25@pignat.org

Tested push-pull and open-drain configurations on a PC Engines APU2,
with UART C and D switched to GPIO in the firmware.

The code is the author's; Claude (Opus 5.5 and Fable 5.1) reviewed it
and drafted this changelog.

Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
Link: https://patch.msgid.link/20261103162738.135836-1-p.pisati@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

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