Bluetooth: hci_bcm: Increase host baudrate for CYW55572 in autobaud mode

Add device specific data for max baudrate in autobaud mode. This allows the
host to use a baudrate higher than "init speed" when loading FW in autobaud
mode.

The device specific max baudrate in autobaud mode for CYW55572 is set to
921600 bps. Devices without device specific max baudrate in autobaud mode
will use init speed as before. If no device specific init speed has been
specified, it will default to the bcm_proto default 115200 bps.

The increased baud rate improves FW load time. The exact load time will
depend on the specific system and FW being used. As a rough indication,
the FW load time dropped from ~9s @ 115.2kbps to ~1.7s @ 921.6kbps in one
test.

Signed-off-by: Hakan Jansson <hakan.jansson@infineon.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>