Bluetooth: replace list_for_each with list_for_each_entry whenever possible

When all items in the list have the same type there is no much of a point
to use list_for_each except if you want to use the list pointer itself.

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