color-lcms: print profile id instead of pointer

Pointer values are hard to track for humans, being long numbers. Now
that we have unique id for each color profile, print that instead of the
pointer. It is a small number easy to track for humans.

Profile id numbers do get re-used aggressively, so you have to keep
track of what is being destroyed and created over time when reading
logs. Pointers had the same caveat, just a lot more random.

The prefix 'p' indicates "profile", just in case we use another id space
for some other thing similarly.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>