efi_selftest: check installation of the device tree

The unit test checks if a device tree is installed. It requires that the
'compatible' property of the root node exists. If available it prints the
'serial-number' property.

The serial-number property is derived from the environment variable
'serial#'. This can be used to check if the image_setup_libfdt() function
is executed.

A Python test is supplied. It sets a value for serial# and checks that the
selftest shows this as serial-number.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index c4bdbdf..88c4484 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -19,6 +19,7 @@
 efi_selftest_devicepath.o \
 efi_selftest_events.o \
 efi_selftest_exitbootservices.o \
+efi_selftest_fdt.o \
 efi_selftest_gop.o \
 efi_selftest_manageprotocols.o \
 efi_selftest_snp.o \