USB: PHY: msm: Clear A_BUS_SUSPEND on cable disconnect

A_BUS_SUSPEND is set on device mode bus-suspend and
cleared on bus-resume. But, bus-resume may not happen
if cable disconnect happens in suspend. This results
in LPM sequence executing as if LPM on bus-suspend is
triggered. Fix this by clearing A_BUS_SUSPEND after
stopping peripheral mode which happens before low
power mode routine is executed.

Change-Id: I186021c3046d5c98b1da7735e057c537652443f0
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>