[POWERPC] Add docs for Freescale PowerQUICC SATA device tree nodes

Signed-off-by: Li Yang <[e-mail]>
Signed-off-by: Kumar Gala <[e-mail]>

Documentation/powerpc/booting-without-of.txt

···
 		};
 	};
 
+    * Freescale 8xxx/3.0 Gb/s SATA nodes
+
+    SATA nodes are defined to describe on-chip Serial ATA controllers.
+    Each SATA port should have its own node.
+
+    Required properties:
+    - compatible        : compatible list, contains 2 entries, first is
+			 "fsl,CHIP-sata", where CHIP is the processor
+			 (mpc8315, mpc8379, etc.) and the second is
+			 "fsl,pq-sata"
+    - interrupts        : <interrupt mapping for SATA IRQ>
+    - cell-index        : controller index.
+                              1 for controller @ 0x18000
+                              2 for controller @ 0x19000
+                              3 for controller @ 0x1a000
+                              4 for controller @ 0x1b000
+
+    Optional properties:
+    - interrupt-parent  : optional, if needed for interrupt mapping
+    - reg               : <registers mapping>
+
+   Example:
+
+	sata@18000 {
+		compatible = "fsl,mpc8379-sata", "fsl,pq-sata";
+		reg = <0x18000 0x1000>;
+		cell-index = <1>;
+		interrupts = <2c 8>;
+		interrupt-parent = < &ipic >;
+        };
 
    More devices will be defined as this spec matures.