ARM: sun5i: Allow PLL3 2x fixed factor clock to change PLL3 rate

In order to be able to properly generate its pixel clock, the pll3-2x fixed
factor needs to be able to change the PLL3 rate too.

Add the needed extra compatible so that it behaves that way.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>