msm: npu: Support to vote multiple bus slaves

NPU may need to vote multiple bus slaves in order to work
properly. And only vote minimum bandwidth for bus slave
MSM_BUS_SLAVE_CLK_CTL.

Change-Id: I6d03828829cedbccfd805121aabcec26df53fe10
Signed-off-by: Jilai Wang <jilaiw@codeaurora.org>