When running Cinnamon I see way too many pairs of these messages: many
per second. Get rid of them as they're just telling us FBC is working
as expected. We already have the messages for enable/disable, so we
don't really need messages for activation/deactivation.

v2: Rebase after changing the patch order.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/