Fix utest-led-json.cpp should not depend on use-json

- The intent behind this commit is to fix the utest-led-json.cpp
  should not depend on use-json, because use-json is for production
  code and it should not affect test code.

Tested: built phosphor-led-manager successfully and Unit Test passes.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: Ia19b68d0167fd8c690ad1b15d29c266e9e77d90b
diff --git a/test/meson.build b/test/meson.build
index 059d13c..ee3abfc 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -28,12 +28,9 @@
 tests = [
   'utest.cpp',
   'utest-serialize.cpp',
+  'utest-led-json.cpp',
 ]
 
-if get_option('use-json').enabled()
-  tests += ['utest-led-json.cpp']
-endif
-
 foreach t : tests
   test(t, executable(t.underscorify(), t,
                      test_sources,