cnss: Use the tsf gpio pin to indicate if tsf enable or not

Get the tsf gpio pin to check if tsf feature enable or not,
if not enable, will not do relevant tsf operation, which can
avoid to print some error message that not needed.

Change-Id: Iab59d4c3c4105824b3fe185311b5afc3ab28d324
Signed-off-by: Chaoli Zhou <zchaoli@codeaurora.org>