clk: sunxi-ng: Add maximum rate constraint to NM PLLs

On some NM PLLs, frequency can be set above PLL working range.

Add a constraint for maximum supported rate. This way, drivers can
specify which is maximum allowed rate for PLL.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>