scsi: ufs-qcom: Adjust the order of bus bandwidth voting and unvoting

The bus bandwidth voting is required to be done before the bus clocks
are enabled, and the unvoting is required to be done only after the bus
clocks are disabled.

Change-Id: Ie231d9c373c0d8c8f3dd90b8322ff24fabdfae26
Signed-off-by: Can Guo <cang@codeaurora.org>