PM / devfreq: Add MSM BIMC bwmon support for bw_hwmon governor

The BIMC bwmon device supports monitoring read/write traffic from each BIMC
master port. It also has the capability to raise an IRQ when the traffic
count exceeds a programmable threshold. This allows for it to be used with
the bw_hwmon governor to scale the BW requests from each BIMC master.

Change-Id: Ie8a1471226411e23954ed556292186a5a864ddc1
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rama Aparna Mallavarapu <aparnam@codeaurora.org>