sonypi - Move sonypi.txt to Documentation/laptops

Also update references to sonypi.txt in Kconfig.

Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
CC: Mattia Dongili <malattia@linux.it>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/Documentation/laptops/00-INDEX b/Documentation/laptops/00-INDEX
index c5bac77..dbe1759 100644
--- a/Documentation/laptops/00-INDEX
+++ b/Documentation/laptops/00-INDEX
@@ -2,5 +2,7 @@
 	- This file
 sony-laptop.txt
 	- Sony Notebook Control Driver (SNC) Readme.
+sonypi.txt
+	- info on Linux Sony Programmable I/O Device support.
 thinkpad-acpi.txt
 	- information on the (IBM and Lenovo) ThinkPad ACPI Extras driver.