Let atrace HAL look with tracefs in /sys/kernel/tracing as well.

With this change, atrace HAL will look for tracefs in
/sys/kernel/tracing first and /sys/kernel/debug/tracing second.

Bug: 185427606
Test: systrace
Change-Id: I5ba8d299fa7173b4c6861518bae93618a77be81a
3 files changed