efi_selftest: add a test for ResetSystem()

The unit test will reset the system by calling the ResetSystem() runtime
service before or after ExitBootServices() according to the users choice
by setting environment variable efi_selftest to:

* 'reset system' or
* 'reset system runtime'.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index 45ce685..85fe8e1 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -31,6 +31,7 @@
 efi_selftest_memory.o \
 efi_selftest_open_protocol.o \
 efi_selftest_register_notify.o \
+efi_selftest_reset.o \
 efi_selftest_set_virtual_address_map.o \
 efi_selftest_textinput.o \
 efi_selftest_textinputex.o \