In case of hci send frame failure, skb is still owned
by the caller (hci_core) and then should not be freed.

This fixes crash on dragonboard-410c when sending SCO
packet. skb is freed by both btqcomsmd and hci_core.

Fixes: 1511cc75 ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>