meta-phosphor: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I588025b614416c43aa2d053765ab53bacf890cb5
diff --git a/meta-phosphor/recipes-support/cjson/cjson_git.bb b/meta-phosphor/recipes-support/cjson/cjson_git.bb
index 096e3c9..1b83dd1 100644
--- a/meta-phosphor/recipes-support/cjson/cjson_git.bb
+++ b/meta-phosphor/recipes-support/cjson/cjson_git.bb
@@ -10,6 +10,6 @@
 
 inherit cmake
 
-FILES_${PN}-dev += "${libdir}/cmake/cJSON/*"
+FILES:${PN}-dev += "${libdir}/cmake/cJSON/*"
 
 EXTRA_OECMAKE = "-DENABLE_CUSTOM_COMPILER_FLAGS=OFF -DENABLE_TARGET_EXPORT=OFF"