CHROMIUM: nmi: don't panic when idle on a system with Hyper-Threading

On a Hyper-Threaded system, the perf counter will continue to
tick if a sibling is unhalted. This could cause a false
lockup to be detected.

BUG=chrome-os-partner:4283
TEST=Sameer ran his suspend stress tests and the issue is now fixed.

Change-Id: I9a963c3bf527e415366dec9c677d9dc2e7d6b1ed
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/1917
Reviewed-by: Sameer Nanda <snanda@chromium.org>
2 files changed