irqchip/stm32-exti: Add STM32MP13 support

Enhance stm32-exti driver to support STM32MP13 SoC. This SoC uses the same
hardware version than STM32MP15. Only EXTI line mapping is changed and
following EXTI lines are supported: GPIO, RTC, I2C[1-5], UxART[1-8],
USBH_EHCI, USBH_OHCI, USB_OTG, LPTIM[1-5], ETH[1-2].

Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220202140005.860-3-alexandre.torgue@foss.st.com