Bluetooth: hci_qca: Not send vendor pre-shutdown command for QCA Rome

QCA Rome doesn't support the pre-shutdown vendor hci command, this patch
will check the soc type in qca_power_off() and only send this command
for wcn399x.

Fixes: ae563183

 ("Bluetooth: hci_qca: Enable power off/on support during hci down/up for QCA Rome")
Signed-off-by: Rocky Liao <rjliao@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>