Bluetooth: UUID: Fix conversion to 128 bit format

The current format used is a swap of RFC 4122 thus the 16 bit values do
come at the end not at the beggining and data need to be swapped.

Change-Id: I38a27cdf82a28d28e47675f719772278d85deaaa
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>