package/json-c: set JSON_C_CPE_ID_VALID

cpe:2.3:a:json-c_project:json-c is a valid CPE identifier for this
package:

  https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe%3A2.3%3Aa%3Ajson-c_project%3Ajson-c

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/json-c/json-c.mk

@@ -9,6 +9,7 @@ JSON_C_SITE = https://s3.amazonaws.com/json-c_releases/releases
 JSON_C_INSTALL_STAGING = YES
 JSON_C_LICENSE = MIT
 JSON_C_LICENSE_FILES = COPYING
+JSON_C_CPE_ID_VALID = YES
 
 $(eval $(cmake-package))
 $(eval $(host-cmake-package))