Bluetooth: Fix UUID values in debugfs file

The uuid entry struct is used for the UUID byte stream. That is
actually the wrong value. The correct value is uuid->uuid.

Besides fixing this up, use the %pUb modifier to print the UUID
string. However since the UUID is stored in big endian with
reversed byte order, change the byte order before printing.

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