dm: pci: Add driver model tests for PCI

Add some basic tests to check that things work as expected with sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 612aa95..8281779 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -21,4 +21,5 @@
 obj-$(CONFIG_DM_SPI) += spi.o
 obj-$(CONFIG_DM_SPI_FLASH) += sf.o
 obj-$(CONFIG_DM_I2C) += i2c.o
+obj-$(CONFIG_DM_PCI) += pci.o
 endif