package/libffi: add LIBFFI_CPE_ID_VENDOR

cpe:2.3:a:libffi_project:libffi is a valid CPE identifier for this
package:

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

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libffi/libffi.mk

@@ -9,6 +9,7 @@ LIBFFI_SITE = \
 	https://github.com/libffi/libffi/releases/download/v$(LIBFFI_VERSION)
 LIBFFI_LICENSE = MIT
 LIBFFI_LICENSE_FILES = LICENSE
+LIBFFI_CPE_ID_VENDOR = libffi_project
 LIBFFI_INSTALL_STAGING = YES
 # We're patching Makefile.am
 LIBFFI_AUTORECONF = YES