Bluetooth: btusb: Fixed too many in-token issue for Mediatek Chip.

[ Upstream commit 8454ed9f ]

This patch reduce in-token during download patch procedure.
Don't submit urb for polling event before sending hci command.

Signed-off-by: mark-yw.chen <mark-yw.chen@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>