Request for adding state in ftrace_importer.html

[youngjae24]

After kernel 4.14, prev_state of sched_switch was added.
It is 'I' state - TASK IDLE
When I see systrace.html in chrome, 'IDLE' is not displayed but 'UNKNOWN' is displayed.
I think 'I' state needs to be added in ftrace_importer.html

Ftrace information
kworker/u16:7-16309 [003] d..2 61197.472005: sched_switch: prev_comm=kworker/u16:7 prev_pid=16309 prev_prio=120 prev_state=I ==> next_comm=swapper/3 next_pid=0 next_prio=120