Bluetooth: Fixed BT ST Channel reg order

Reordered the BT ST channel registration, to make sure that the
event channel is registered before all others. This prevents a
situation where incoming events may cause kernel panic in the ST
driver if the event channel is not yet registered to handle
incoming events.In addition, the deregistration of the channels
was also modified, to be in the reversed order of the registration,
to allow the event channel to be the last one unregistered.

Signed-off-by: Chen Ganir <chen.ganir@ti.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>