drm/msm: allow sde_atrace to show up on different process

Currently trace always shows up on same process as caller, add
an additional function to allow attaching trace to any process.

Change-Id: I8fc124f9d1cfae28d1868a9a3067d0e92eda934e
Signed-off-by: Adrian Salido <salidoa@google.com>
(cherry picked from commit 52ba2d3585eb49c5d5b90b3cd75e0abe5c984dad)
Signed-off-by: Christopher Braga <cbraga@codeaurora.org>
Signed-off-by: Samantha Tran <samtran@codeaurora.org>