Revert "tracing: Switch trace_events_hist.c code over to use guard()"

This reverts commit 77b7dbd3 which is
commit 2b36a97a upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I854ce99a0681c2643d2fec777968dc4549dd19f5
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>