acpi: Add a simple sandbox test

Add a sandbox test for the basic ACPI functionality we have so far.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index dd1ceff..3daf8a5 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -13,6 +13,7 @@
 # subsystem you must add sandbox tests here.
 obj-$(CONFIG_UT_DM) += core.o
 ifneq ($(CONFIG_SANDBOX),)
+obj-$(CONFIG_ACPIGEN) += acpi.o
 obj-$(CONFIG_SOUND) += audio.o
 obj-$(CONFIG_BLK) += blk.o
 obj-$(CONFIG_BOARD) += board.o