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: I67d3a2323eed6ab4450b0e201564fc12e6696056
Signed-off-by: Da Hoon Pyun <dpyun@codeaurora.org>