cpu/sam0: prevent disabled irq from being called
cpu/sam0: prevent disabled irq from being called

Reported-by: biboc <f3c6093e46a54b3a0728c33abe7f9d0c8cd1e4b4@gmail.com>
Signed-off-by: dylad <d56dfe611c7cd6204525c7c9b6afc5e84aed0f5d@mesotic.com>

kaspar030/RIOT,kaspar030/RIOT,jasonatran/RIOT,kYc0o/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,OlegHahm/RIOT,kYc0o/RIOT,OlegHahm/RIOT,kYc0o/RIOT,ant9000/RIOT,ant9000/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,miri64/RIOT,miri64/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,kaspar030/RIOT,ant9000/RIOT,ant9000/RIOT,jasonatran/RIOT,ant9000/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,miri64/RIOT,miri64/RIOT,jasonatran/RIOT,jasonatran/RIOT,miri64/RIOT,kaspar030/RIOT,OlegHahm/RIOT,kaspar030/RIOT