USB: dwc3-msm: Check endpoint status and request queued or not first

When function driver calls dwc3_msm_ep_queue() to queue endless request,
first check endpoint status and whether any request already queued or not.
If that is the case, return error. Else go ahead with queuing request
to USB HW. This helps in resolving the crash seen when request is being
queued again.

Change-Id: I3d6a603c693d1df36719f57684ffad409e1a0e78
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>