Diag event processing is stuck due to skb allocation failure.
SKb allocation is done using flag GFP_KERNEL which results
in the kworker thread to sleep and results in wmi workqueue
timer to expire.
Fix is to use GFP_ATOMIC flag for skb allocation for
diag data.
Change-Id: Ifa715df89ae06b17d4dc1506ea4f3c4e2af31f33
CRs-Fixed: 2559679