Bluetooth: Classic: SDP: Improve UUID 128 support

In current implementation, the UUID 128 is not well supported. The
found issue includes,
Issue 1: No clear byte order of the UUID 128 in local SDP record.
Issue 2: No clear byte order of the UUID 128 of the SDP discover
parameter.

For issue 1,
Add the description to note that if the SDP attribute type is
`BT_SDP_UINT128`, `BT_SDP_INT128`, and `BT_SDP_UUID128`, the byte
order should be little-endian.

And swap the 128bit from little-endian to big-endian when responding
the peer SDP discovery request.

For issue 2,
Add the description to note that if the SDP discovery type is
`Service Search` and `Service Search Attribute`, and UUID is UUID 128,
the passed UUID data of the discovery request parameter should be
represented as the little-endian byte-order sequence.

And swap the 128bit from little-endian to big-endian when packing the
SDP discovery packet.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>