wcnss: Avoid turning off wcnss power for multiple time

Avoid calling wcnss power turn off if wcnss power is not
turn on. serialize wcnss power functionality.

Change-Id: I4cd70bb56c50716624297fa8038b557e88dde813
CRs-Fixed: 667276
Signed-off-by: Hardik Kantilal Patel <hkpatel@codeaurora.org>