ARM: dts: Move all Cygnus peripherals into axi bus

Move all Cygnus peripherals to be under the "axi" bus node of type
"simple-bus"

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>