msm: ADSPRPC: Awake PM with a timeout

Awake PM with a timeout in kernel soon after response from DSP to
keep the system awake and allow the ioctl call reach user space from
kernel space.

Change-Id: If518e17ec300565af2d16feca0524e741790ba7f
Acked-by: Himateja Reddy <hmreddy@qualcomm.com>
Signed-off-by: Anirudh Raghavendra <araghave@codeaurora.org>