mm: mm_event: comment about enum event type ordering

Perfetto uses binary tracing so we shouldn't reordring/removing
the event type. Describe it more explicitly.

Bug: 80168800
Change-Id: I7fa415b0ddc803e9ad81590f692a46bb416b2dd9
Signed-off-by: Minchan Kim <minchan@google.com>
(cherry picked from commit ab281c5bf4753b1048d8a059342f89a0d24e9169)
1 file changed