Disable low power/deep sleep modes when they are not enabled in Kconfig.
Otherwise if only low power modes are enabled (but no deep sleep),
Zephyr will try to swich to the lowest power mode (deep sleep) anyway,
only to discover that it's not availiable, resulting in no low power
mode at all being used.
By disabling the modes here if they are not enabled in Kconfig,
policy_residency will switch to the lowest low power mode instead.
Signed-off-by: Benjamin Valentin <benjamin.valentin@ml-pa.com>