Bluetooth: make use of connection number to optimize the scheduler

This checks if there is any existing connection according to its type
before start iterating in the list and immediately stop iterating when
reaching the number of connections.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>