Bluetooth: btusb: use default nvm if boardID is 0 for wcn6855.

[ Upstream commit ca17a5cc ]

if boardID is 0, will use the default nvm file without surfix.

Signed-off-by: Tim Jiang <tjiang@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>