package/dovecot: add CVE trailer in patch

Since Buildroot commit [1] the patches that fixes a security
vulnerability needs to reference the fixed vulnerability.

This patch adds the relevant information to the patch header.

[1] 1167d0ff3d docs/manual: mention CVE trailer

Signed-off-by: Thomas Perale <thomas.perale@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/dovecot/0001-auth-Fix-handling-passdbs-with-identical-driver-args.patch

@@ -12,6 +12,7 @@ Fixed by moving mechanisms and username_filter from struct passdb_module
 to struct auth_passdb, which is where they should have been in the first
 place.
 
+CVE: CVE-2022-30550
 Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
 ---
  src/auth/auth-request.c |  6 +++---