Spreadtrum cp_dump bindings

Required properties:
- compatible: "sprd,cp_dump".
- sprd,sys-bus-ctrl-sp: Should contain the base address, offset and bit for sp sysbusctrl.
- sprd,sys-bus-ctrl-ch: Should contain the base address, offset and bit for ch sysbusctrl.

Example:

	nr_cp_dump: cp_dump {
		compatible = "sprd,cp_dump";
		sprd,sys-bus-ctrl-sp = <&aon_apb_regs 0x0128 0x1>;
		sprd,sys-bus-ctrl-ch = <&aon_apb_regs 0x0124 0x1>;
	};