package/polkit: fix typo in POLKIT_IGNORE_CVES

The POLKIT_IGNORE_CVES variable was missing a "S",
therefore the CVE still showed up in the wrong column.

Signed-off-by: Daniel Lang <d.lang@abatec.at>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/polkit/polkit.mk

@@ -12,7 +12,7 @@ POLKIT_CPE_ID_VENDOR = polkit_project
 POLKIT_INSTALL_STAGING = YES
 
 # Fix was comitted in a2bf5c9c83b6ae46cbd5c779d3055bff81ded683
-POLKIT_IGNORE_CVE = CVE-2021-4034
+POLKIT_IGNORE_CVES += CVE-2021-4034
 
 POLKIT_DEPENDENCIES = \
 	duktape libglib2 host-intltool expat $(TARGET_NLS_DEPENDENCIES)