qcacld-3.0: Acquire a wakelock whenever packet capture mode is enabled

Whenever packet capture mode is enabled, all packets are forwarded
to host from firmware which causes frequent wakeups if WOW suspend is
allowed. This leads to flooding of WMI transactions due to WOW
suspend/wakeup and other WMI events due to packet capture mode over CE.
So, to reduce number of WMI transactions due to frequent suspend and
then wakeup due to enablement of packet capture mode, acquire a
wakelock and prevent runtime suspend whenever packet capture mode is
enabled.

Change-Id: I71b73e7327e14890dc8509b81b22e8b5611cbac6
CRs-Fixed: 3603566
(cherry picked from commit d1fe6088)