The alarm status for this entity. It does not include
the alarms raised on child components within its
containment hierarchy.
A value of 'unknown' means that this entity is
unable to report alarm state. Note that this differs
from 'indeterminate', which means that alarm state
is supported and there are alarms against this entity,
but the severity of some of the alarms is not known.
If no bits are set, then this entity supports reporting
of alarms, but there are currently no active alarms
against this entity.