drivers: interrupt_controller: initial support for GD32 EXTI

Add initial support for the GigaDevice External Interrupt Controller.
This driver is required to manage GPIO interrupts. Only EXTI lines 0 to
15 are supported for now (no LVD, RTC, etc.). Driver can be extended in
the future to add support for extra EXTI lines.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
5 files changed