FROMLIST: tracing: Prepare to add preempt and irq trace events

In preparation of adding irqsoff and preemptsoff enable and disable trace
events, move required functions and code to make it easier to add these events
in a later patch. This patch is just code movement and no functional change.

Change-Id: I587d411da5efbc4959bcccd7a05c7a66c231e1e0
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@android.com
Link: https://patchwork.kernel.org/patch/9988159/


Signed-off-by: Joel Fernandes <joelaf@google.com>