lisa.analysis.tasks: Do not include TASK_UNKNOWN in reported states
lisa.analysis.tasks: Do not include TASK_UNKNOWN in reported states

Since the kernel will not emit TASK_UNKNOWN state (which is purely
internal to LISA), remove it from the list of states used to parse task
states.

ARM-software/lisa,credp/lisa,credp/lisa,credp/lisa,ARM-software/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa