ARM: Kirkwood: switch to DT clock providers

ARM: Kirkwood: switch to DT clock providers

With true DT clock providers available switch Kirkwood clock setup in
DT- enabled boards. While AUXDATA can be removed completely from bus
probing, some devices still don't know about DT. Therefore, some clkdev
aliases are created until these devices also move to DT.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>