Bluetooth: btusb: Improve stability for QCA devices

Bluetooth: btusb: Improve stability for QCA devices

BugLink: https://bugs.launchpad.net/bugs/1967067
WCN6855 2.1 will reset to apply firmware downloaded, so wait
a moment for reset done then go ahead to improve stability.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
(cherry picked from commit 599ece4f8f073097904d411ee70280a2ec890ad3)
Signed-off-by: You-Sheng Yang <vicamo.yang@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>