Bluetooth: hci_qca: allow max-speed to be set for QCA9377 devices

Move the read of max-speed from device-tree out of the qca_is_wcn399x
if block so oper_speed can be set for QCA9377 devices as well.

Suggested-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>