usb: dwc3: msm: Move state machine variables

Move the OTG sm_work and related state variables from dwc3_otg
to struct dwc3_msm.

Change-Id: Iba135d0eaacbd40d646f0cb57a5bdeaf69e7c8d5
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Azhar Shaikh <azhars@codeaurora.org>