clk: add support for berlin plls

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
ARM: berlin/dt: add cpupll and syspll support to BG2Q

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
ARM: berlin/dt: add cpupll and syspll support to BG2CD

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>