audit: allow audit matching on inode gid

Much like the ability to filter audit on the uid of an inode collected, we
should be able to filter on the gid of the inode.

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 55cb3da..e36aa37 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -224,6 +224,7 @@
 #define AUDIT_DIR	107
 #define AUDIT_FILETYPE	108
 #define AUDIT_OBJ_UID	109
+#define AUDIT_OBJ_GID	110
 
 #define AUDIT_ARG0      200
 #define AUDIT_ARG1      (AUDIT_ARG0+1)