arm: exynos: add busfreq trace events

arm: exynos: add busfreq trace events

Add exynos_busfreq_target_{mif,int} events to monitor operation
and remove printk that is now duplicate information.

Signed-off-by: Sam Leffler <sleffler@chromium.org>
BUG=chrome-os-partner:13801
TEST=monitor evevents while playing video

Change-Id: I0e82ad4afb72e6b4664dbd95d206186864a9266e
Reviewed-on: https://gerrit.chromium.org/gerrit/32560
Reviewed-by: Bryan Freed <bfreed@chromium.org>
Commit-Ready: Sam Leffler <sleffler@chromium.org>
Tested-by: Sam Leffler <sleffler@chromium.org>