tracing/timerlat: Print stacktrace in the IRQ handler if needed

tracing/timerlat: Print stacktrace in the IRQ handler if needed

If print_stack and stop_tracing_us are set, and stop_tracing_us is hit
with latency higher than or equal to print_stack, print the
stack at the IRQ handler as it is useful to define the root cause for
the IRQ latency.

Link: https://lkml.kernel.org/r/fd04530ce98ae9270e41bb124ee5bf67b05ecfed.1652175637.git.bristot@kernel.org
Cc: Juri Lelli <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>