Bluetooth: hci_qca: Add qca_power_on() API to support both wcn399x and Rome power up

This patch adds a unified API qca_power_on() to support both wcn399x and
Rome power on. For wcn399x it calls the qca_wcn3990_init() to init the
regulators, and for Rome it pulls up the bt_en GPIO to power up the btsoc.
It also moves all the power up operation from hdev->open() to
hdev->setup().

Signed-off-by: Rocky Liao <rjliao@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>