USB: msm_otg: Increment PM usage counter for suspend failure cases

The current code does not return error from runtime_suspend hook,
even if fail to enter into low power mode.  OTG driver will not
increment PM runtime usage counter outside LPM.  Runtime PM thinks,
our device is in LPM and ignores the subsequent PM usage decrements.
Hence increment the PM usage counter explicitly if suspend fails.

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>