package/flac: set FLAC_CPE_ID_VALID

cpe:2.3:a:flac_project:flac is a valid CPE identifier for this package:

  https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe%3A2.3%3Aa%3Aflac_project%3Aflac

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/flac/flac.mk

@@ -11,6 +11,7 @@ FLAC_INSTALL_STAGING = YES
 FLAC_DEPENDENCIES = $(if $(BR2_PACKAGE_LIBICONV),libiconv)
 FLAC_LICENSE = Xiph BSD-like (libFLAC), GPL-2.0+ (tools), LGPL-2.1+ (other libraries)
 FLAC_LICENSE_FILES = COPYING.Xiph COPYING.GPL COPYING.LGPL
+FLAC_CPE_ID_VALID = YES
 
 # patch touching configure.ac
 FLAC_AUTORECONF = YES