openpower: occ: Add nlohmann-json dependency

openpower-occ-control has been using nlohmann-json for a while and
successfully compiling by chance. Add it to the dependencies.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Change-Id: I8efc98d44eee32ad96fcc1472955fa0858d1569a
diff --git a/meta-openpower/recipes-phosphor/occ/openpower-occ-control_git.bb b/meta-openpower/recipes-phosphor/occ/openpower-occ-control_git.bb
index 10d495b..593b52b 100644
--- a/meta-openpower/recipes-phosphor/occ/openpower-occ-control_git.bb
+++ b/meta-openpower/recipes-phosphor/occ/openpower-occ-control_git.bb
@@ -35,6 +35,7 @@
         ${PYTHON_PN}-pyyaml-native \
         ${PYTHON_PN}-setuptools-native \
         ${PYTHON_PN}-mako-native \
+        nlohmann-json \
         "
 
 RDEPENDS:${PN} += "phosphor-state-manager-obmc-targets"