test: add test for lib/lmb.c

Add basic tests for the lmb memory allocation code used to reserve and
allocate memory during boot.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/lib/Makefile b/test/lib/Makefile
index ea68fae..5a636aa 100644
--- a/test/lib/Makefile
+++ b/test/lib/Makefile
@@ -3,3 +3,4 @@
 # (C) Copyright 2018
 # Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
 obj-y += hexdump.o
+obj-y += lmb.o