Add trace events to track the progress of a GPU submission
msm_gpu_submit occurs at the beginning of the submissions,
msm_gpu_submit_flush happens when the submission is put on
the ringbuffer and msm_submit_flush_retired is sent when
the operation is retired.

To make it easier to track the operations a unique sequence
number is assigned to each submission and displayed in each
event output so a human or a script can easily associate
the events related to a specific submission.
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>