Bluetooth: hci_uart: Remove the manual protocol init message

The init function for each HCI UART protocol prints the same on success
and failure. This information is so generic, remove it and let the main
HCI UART handling print it instead.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>