ANDROID: hardlockup: detect hard lockups without NMIs using secondary cpus

This patch adds back the hardlockup detection without NMIs from
<aaf78ec6>("ANDROID: hardlockup: detect hard lockups without NMIs
using secondary cpus") which was reverted after the hard lockup detection
logic was moved to a separate file in <b969a240>("kernel/watchdog.c:
move hardlockup detector to separate file").

Change-Id: If6a24b379d29fa582344fe57d26df4bd2b8cc89f
Signed-off-by: Kyle Yan <kyan@codeaurora.org>