Revert "Revert "ACPI: dock driver""

This reverts 953969ddf5b049361ed1e8471cc43dc4134d2a6f commit.
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index bb5b80a..bce7ca2 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -42,6 +42,7 @@
 obj-$(CONFIG_ACPI_BUTTON)	+= button.o
 obj-$(CONFIG_ACPI_EC)		+= ec.o
 obj-$(CONFIG_ACPI_FAN)		+= fan.o
+obj-$(CONFIG_ACPI_DOCK)		+= dock.o
 obj-$(CONFIG_ACPI_VIDEO)	+= video.o 
 obj-$(CONFIG_ACPI_HOTKEY)	+= hotkey.o
 obj-y				+= pci_root.o pci_link.o pci_irq.o pci_bind.o