Add support for GPIOs connected to the MCU on the Turris Omnia board.

This includes:
- front button pin
- enable pins for USB regulators
- MiniPCIe / mSATA card presence pins in MiniPCIe port 0
- LED output pins from WAN ethernet PHY, LAN switch and MiniPCIe ports
- on board revisions 32+ also various peripheral resets and another
  voltage regulator enable pin
Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/r/20240701113010.16447-4-kabel@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>