Required properties:
- compatible : shall be one of the following:
"allwinner,sun4i-osc-clk" - for a gatable oscillator
- "allwinner,sun4i-pll1-clk" - for the main PLL clock
+ "allwinner,sun4i-pll1-clk" - for the main PLL clock and PLL4
"allwinner,sun6i-a31-pll1-clk" - for the main PLL clock on A31
"allwinner,sun4i-cpu-clk" - for the CPU multiplexer clock
"allwinner,sun4i-axi-clk" - for the AXI clock