pkg/nimble: optimize HCI config to save RAM
pkg/nimble: optimize HCI config to save RAM

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