msm: msm_bus: remove the buspm module from kernel

Remove the buspm module from msm_bus since it adds
no functionality to the bus bandwidth aggregation
driver. It is a loadable module used for profiling
purposes.

Change-Id: Ia0d21eb7e48d3cb2a74d4fae5ee4fb2fd449ea9f
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>