Bluetooth: Fix long_term_keys debugfs output

The code was previously iterating the wrong list (and what's worse
casting entries to a type which they were not) and also missing a proper
line terminator when printing each entry. The code now also prints the
LTK type in hex for easier comparison with the kernel-defined values.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>