gpio: tps65219: add GPIO support for TPS65219 PMIC

Add support for TPS65219 PMICs GPIO interface.

3 GPIO pins:
- GPIO0 only is IO but input mode reserved for MULTI_DEVICE_ENABLE usage.
- GPIO1 and GPIO2 are Output only and referred as GPO1 and GPO2 in spec.

GPIO0 is statically configured as input or output prior to Linux boot.
it is used for MULTI_DEVICE_ENABLE function.
This setting is statically configured by NVM.
GPIO0 can't be used as a generic GPIO (specification Table 8-34).
It's either a GPO when MULTI_DEVICE_EN=0 or a GPI when MULTI_DEVICE_EN=1.

Datasheet describes specific usage for non standard GPIO.

Datasheet: https://www.ti.com/lit/ds/symlink/tps65219.pdf


Co-developed-by: Jonathan Cormier <jcormier@criticallink.com>
Signed-off-by: Jonathan Cormier <jcormier@criticallink.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jerome Neanne <jneanne@baylibre.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>