drivers: acpi: Fix dependency for ACPI_HOTPLUG_CPU

Fix the following build warning:

warning: (ACPI_HOTPLUG_CPU) selects ACPI_CONTAINER which has unmet direct dependencies (ACPI && EXPERIMENTAL)
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Kconfig

@@ -208,7 +208,7 @@ config ACPI_IPMI
 
 config ACPI_HOTPLUG_CPU
 	bool
-	depends on ACPI_PROCESSOR && HOTPLUG_CPU
+	depends on EXPERIMENTAL && ACPI_PROCESSOR && HOTPLUG_CPU
 	select ACPI_CONTAINER
 	default y