ACPI: thinkpad-acpi: update documents for the new location

Update documentation to reflect the new location of the
thinkpad-acpi driver.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: NLen Brown <len.brown@intel.com>

Documentation/laptops/thinkpad-acpi.txt

@@ -16,7 +16,8 @@ supported by the generic Linux ACPI drivers.
 This driver used to be named ibm-acpi until kernel 2.6.21 and release
 0.13-20070314.  It used to be in the drivers/acpi tree, but it was
 moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel
-2.6.22, and release 0.14.
+2.6.22, and release 0.14.  It was moved to drivers/platform/x86 for
+kernel 2.6.29.
 
 The driver is named "thinkpad-acpi".  In some places, like module
 names, "thinkpad_acpi" is used because of userspace issues.