msm: msm_bus: Introduce multi level BKE limiting.

Introduce multi level BKE throttling for BIMC masters. By specifying an
array of thresholds and limiting bandwidth values, multiple levels of
master throttling can be achieved.

Change-Id: Ic3b483d3e987266e8f37e66dff8bedd49ddd1d4d
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>