Get rid of the extra bt_disable call when turning on airplane mode

Get rid of enabling bt when in airplane mode.

Current code has 2 paths that trying to place bluetooth in cold state when
turning airplane mode on. This caused extra call of bt_disable that
causing a kernel sleep failure. The fix removes one of the sys call.
This CL keeps Bluetooth in cold state after turning airplane mode on
instead of seting it to hotoff state
bug 6563480

Change-Id: I30c413707157acb4a8e83ded9452256cf6260899