hwmon: (k8temp) documentation: update URL of datasheet

The old URL is dead.
Signed-off-by: Robert Karszniewicz <avoidr@firemail.cc>
Link: https://lore.kernel.org/r/7139bc7707c24bd4dd7eb323e2da90105a3de9c1.1563522498.git.avoidr@firemail.ccSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/k8temp.rst

@@ -9,7 +9,7 @@ Supported chips:
 
     Addresses scanned: PCI space
 
-    Datasheet: http://support.amd.com/us/Processor_TechDocs/32559.pdf
+    Datasheet: http://www.amd.com/system/files/TechDocs/32559.pdf
 
 Author: Rudolf Marek