ARM: sunxi: Update datasheet documentation

We have access to more documentation now, especially the user manuals,
so add the links to them, and do so minor comestic changes while we're
at it.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Documentation/arm/sunxi/README

@@ -3,17 +3,22 @@ ARM Allwinner SoCs
 
 This document lists all the ARM Allwinner SoCs that are currently
 supported in mainline by the Linux kernel. This document will also
-provide links to documentation and or datasheet for these SoCs.
+provide links to documentation and/or datasheet for these SoCs.
 
 SunXi family
 ------------
+  Linux kernel mach directory: arch/arm/mach-sunxi
 
   Flavors:
-        Allwinner A10 (sun4i)
-                Datasheet       : http://dl.linux-sunxi.org/A10/A10%20Datasheet%20-%20v1.21%20%282012-04-06%29.pdf
+    * ARM Cortex-A8 based SoCs
+      - Allwinner A10 (sun4i)
+        + Datasheet
+	  http://dl.linux-sunxi.org/A10/A10%20Datasheet%20-%20v1.21%20%282012-04-06%29.pdf
+	+ User Manual
+	  http://dl.linux-sunxi.org/A10/A10%20User%20Manual%20-%20v1.20%20%282012-04-09%2c%20DECRYPTED%29.pdf
 
-        Allwinner A13 (sun5i)
-                Datasheet       : http://dl.linux-sunxi.org/A13/A13%20Datasheet%20-%20v1.12%20%282012-03-29%29.pdf
-
-  Core: Cortex A8
-  Linux kernel mach directory: arch/arm/mach-sunxi
+      - Allwinner A13 (sun5i)
+        + Datasheet
+	  http://dl.linux-sunxi.org/A13/A13%20Datasheet%20-%20v1.12%20%282012-03-29%29.pdf
+        + User Manual
+	  http://dl.linux-sunxi.org/A13/A13%20User%20Manual%20-%20v1.2%20%282013-08-08%29.pdf