dock: make dock driver not a module

To avoid dock driver is loaded after other drivers like libata, let's
make dock driver not a module.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Kconfig

@@ -157,7 +157,7 @@ config ACPI_FAN
 	  applications to perform basic fan control (on, off, status).
 
 config ACPI_DOCK
-	tristate "Dock"
+	bool "Dock"
 	depends on EXPERIMENTAL
 	help
 	  This driver adds support for ACPI controlled docking stations and removable