Add a new HCI protocol HCI_UART_AML for the Amlogic Bluetooth
controller. It works on the standard H4 protocol via a 4-wire UART
interface, with baud rates up to 4 Mbps.

The controller supports two types of commands: the TCI commands and the
vendor command. The former is for initial setup including setting baud
rates, downloading fw, starting chip and etc, while the latter is for
dumping firmware versions and setting public address after firmware
updates and normal startup.

It was verified on board of T602 (S905X4 + W265S2).

dmesg:
..
[    5.313450] Bluetooth: HCI UART protocol AML registered
[    6.506052] Bluetooth: hci0: fw_version: date = 42.28, number = 0xb2fd
...
Co-developed-by: Ye He <ye.he@amlogic.com>
Signed-off-by: Ye He <ye.he@amlogic.com>
Signed-off-by: Yang Li <yang.li@amlogic.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>