Bluetooth: hci_qca: unduplicate calls to hci_uart_register_device()

Now that all three branches of the switch end up doing the same thing,
we can move the call to hci_uart_register_device() past it and unify the
error message.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>