During the setup() stage, HCI device drivers expect the chip to
acknowledge its setup() completion via vendor specific frames.

If userspace opens() such HCI device in HCI_USER_CHANNEL [1] mode,
the vendor specific frames are never tranmitted to the driver, as
they are filtered in hci_rx_work().

Allow HCI devices which operate in HCI_USER_CHANNEL mode to receive
frames if the HCI device is is HCI_INIT state.

[1] https://www.spinics.net/lists/linux-bluetooth/msg37345.html

Fixes: 23500189 ("Bluetooth: Introduce new HCI socket channel for user operation")
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>