leds: rainier: Enable PACKAGECONFIG to use json

This enables phosphor-ledmanager to use JSON configuration file

Change-Id: I3cbd0bf6b60e81f9f0a479ad51dab438c708c6c1
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/meta-phosphor/recipes-phosphor/leds/phosphor-led-manager_git.bb b/meta-phosphor/recipes-phosphor/leds/phosphor-led-manager_git.bb
index 55171db..01932d2 100644
--- a/meta-phosphor/recipes-phosphor/leds/phosphor-led-manager_git.bb
+++ b/meta-phosphor/recipes-phosphor/leds/phosphor-led-manager_git.bb
@@ -13,6 +13,9 @@
     ${PN}-faultmonitor \
 "
 
+PACKAGECONFIG ??= ""
+PACKAGECONFIG[use-json] = "--enable-use-json, --disable-use-json"
+
 PACKAGE_BEFORE_PN += "${LED_MGR_PACKAGES}"
 ALLOW_EMPTY_${PN} = "1"