scsi: ufs: Set VS_CORE_CLK with values queried from DT/Clk Driver

Setting the DME_VS_CORE_CLK_CTRL using the Unipro clock frequencies
queried from the Device Tree and the clock driver instead of using
hardcoded values in the UFS driver.

Change-Id: Id39ee17a149ab0f7581931ac4152756f2ee60de2
Signed-off-by: Bao D. Nguyen <nguyenb@codeaurora.org>