dt-bindings: Document Blaize BLZP1600 GPIO driver

dt-bindings: Document Blaize BLZP1600 GPIO driver

This is a custom silicon GPIO driver provided by VeriSilicon
Microelectronics. It has 32 input/output ports which can be
configured as edge or level triggered interrupts. It also provides
a de-bounce feature.
This controller is used on the Blaize BLZP1600 SoC.

Signed-off-by: Nikolaos Pasaloukos <nikolaos.pasaloukos@blaize.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250327-kernel-upstreaming-add_gpio_support-v2-1-bbe51f8d66da@blaize.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>