hwrng: st - Provide DT bindings for ST's Random Number Generator

STMicroelectronics HW Random Number Generator

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Required parameters:

compatible	: Should be "st,rng"

reg		: Base address and size of IP's register map.

clocks		: Phandle to device's clock (See: ../clocks/clock-bindings.txt)

Example:

rng@0xfee80000 {

	compatible      = "st,rng";

	reg		= <0xfee80000 0x1000>;

	clocks          = <&clk_sysin>;

}