USB: cdc-acm: add device id for GW Instek AFG-125

[ Upstream commit 301216044e4c27d5a7323c1fa766266fad00db5e ]

Add device-id entry for GW Instek AFG-125, which has a byte swapped
bInterfaceSubClass (0x20).

Signed-off-by: Nathaniel Quillin <ndq@google.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>