microblaze: Add support for CCF

Add support for CCF for Microblaze.

Old binding:
system_timer: system-timer@41c00000 {
	clock-frequency = <75000000>;
	...
}

New binding:
system_timer: system-timer@41c00000 {
	clocks = <&clk_bus>;
	...
}

Both should be supported for a while

Microblaze clock binding:
clocks {
	#address-cells = <1>;
	#size-cells = <0>;
	clk_bus: bus {
		#clock-cells = <0>;
		clock-frequency = <75000000>;
		clock-output-names = "bus";
		compatible = "fixed-clock";
		reg = <1>;
	} ;
	clk_cpu: cpu {
		#clock-cells = <0>;
		clock-frequency = <75000000>;
		clock-output-names = "cpu";
		compatible = "fixed-clock";
		reg = <0>;
	} ;
} ;

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/include/asm/cpuinfo.h

@@ -91,6 +91,7 @@ extern struct cpuinfo cpuinfo;
 
 /* fwd declarations of the various CPUinfo populators */
 void setup_cpuinfo(void);
+void setup_cpuinfo_clk(void);
 
 void set_cpuinfo_static(struct cpuinfo *ci, struct device_node *cpu);
 void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu);