usb: dwc3-msm: Fix mode of perf vote update error

when two usb controller are enabled, the static value of curr_mode
will be changed by each controller. so we move this value to dwc3_msm
structure.

Change-Id: Ib20bfe7e0f3aeb0e32a3083fe63286998f782a70
CRs-Fixed: 1113949
Signed-off-by: Wumei Fang <wumeif@codeaurora.org>