net: usb: Abort suspend if get_encap response is not sent

After receiving response available notification driver queues
a work to send get_encap response. pm state is set to
RPM_SUSPENDING before interface suspend is initiated. If
interface suspend happens after queuing the work then work
will be executed and blocked until it is done. Work tries to
resume the interface synchronously by calling rpm_resume().
This causes rpm_resume() to wait indefinitely for the pm state
to change from RPM_SUSPENDED to RPM_RESUME which will not
happen until interface suspend returns EBUSY. Hence avoid this
situation by aborting interface suspend if work is pending
or running.

CRs-Fixed: 415208
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
Change-Id: Ib2a079a7107d994f760c0a876736ede3add07ea2