msm: adsprpc: do not vote with PM when CPU is going into suspend

If pending RPC context is interrupted because of CPU going into
suspend state, do not vote with PM to keep the CPU awake. When the
actual response from remote subsystem arrives, rpmsg will wake the
CPU up and once the fastrpc thread is scheduled, then PM vote will
be made to keep the CPU awake until the call returns to userspace.

Change-Id: I0d98a0cd3c8dd787a11a778510a9ad75fc15ee62
Acked-by: Thyagarajan Venkatanarayanan <venkatan@qti.qualcomm.com>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>