msm: msm_bus: Modify AB/IB value sent to rules engine

Rules engine needs to get the max of the requested IB or the aggregated
AB at the node, without this check we may incorrectly apply throttling
rules.

Change-Id: Ib22fe16a056f6648aa10f069992ad5c41452cbca
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>