Bluetooth: hci_qca: Fix suspend/resume functionality failure

@dev parameter of qca_suspend()/qca_resume() represents
serdev_device, but it is mistook for hci_dev and causes
succedent unexpected memory access.

Fix by taking @dev as serdev_device.

Fixes: 41d5b25f

 ("Bluetooth: hci_qca: add PM support")
Signed-off-by: Zijun Hu <zijuhu@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>