platform: msm: msm_bus: Add trace events for bus AB

Add trace events to the ad-hoc bus driver to log
Average BW (AB) that bus driver sends to RPM for
shared slaves.

Change-Id: I8fad0a3b3df6a6be5c659ca371f15fb27710b3f0
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>