hw/misc: Implement STM32L4x5 EXTI

hw/misc: Implement STM32L4x5 EXTI

Although very similar to the STM32F4xx EXTI, STM32L4x5 EXTI generates
more than 32 event/interrupt requests and thus uses more registers
than STM32F4xx EXTI which generates 23 event/interrupt requests.

Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr>
Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20240109160658.311932-2-ines.varhol@telecom-paris.fr
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>