wcnss: Invoke PIL only after completing intialization

Delay PIL operation until all data structures used by WCNSS SMD
interrupt handler are initialized. There could be a race condition
where the SMD interrupt handler is called even before the WCNSS
trigger function is completed.

Change-Id: I6d83e7a67ebb3e7b6efe2b3fbfc2708cca355916
CRs-Fixed: 496402
Signed-off-by: Sameer Thalappil <sameert@codeaurora.org>