mm: cma: add trace events for CMA alloc perf testing

Add cma and migrate trace events to enable CMA allocation
performance to be measured via ftrace.

Change-Id: I1e471e9e21f1a14ce2ed167d8515ccb5f83eb88c
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>