msm: sps: turn off BAM DMA clock after initial config

For power saving, SPS driver will turn off BAM DMA clock after the
initial configuration of BAM DMA. The clients of BAM DMA will vote
for the clock when BAM DMA is used.

Change-Id: I388a21cff3c619ef49705a064d7d5ef760fa9ef8
Signed-off-by: Yan He <yanhe@codeaurora.org>