bootstat: add reboot,longkey sub-reason to known set

regular expression:
- "reboot,longkey,.*" (184)

regex is dependent on:
- https://android-review.googlesource.com/947976

Test: none
Bug: 132955428
Bug: 133520088
Change-Id: I53d13d95ac11ac73273824156363378372a562ed
1 file changed