Bluetooth: Implement a minimum off-time for AON discharge issue

Sometimes it is seen that AON LDO output takes minimum
off-time (worst case 100ms) to fully discharge. If BT is
turned on in this timeframe when AON is not fully discharged
yet ,BT would fail to turn ON.

This fix ensures to
Toggle BT_EN high when WL_EN is already high.
Handle corner case if WL_EN goes low in step 1.
Add 100ms to toggle BT_EN high when WL_EN is low.

Change-Id: Ibe082165788bd9ddb553e6043696bebc5bf4b609
Signed-off-by: Mahesh Kumar Sharma <smahesh@codeaurora.org>