dovecot: add applicable licenses

List all code licenses mentioned in COPYING.

Cc: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/dovecot/dovecot.mk

@@ -8,7 +8,7 @@ DOVECOT_VERSION_MAJOR = 2.2
 DOVECOT_VERSION = $(DOVECOT_VERSION_MAJOR).31
 DOVECOT_SITE = http://www.dovecot.org/releases/$(DOVECOT_VERSION_MAJOR)
 DOVECOT_INSTALL_STAGING = YES
-DOVECOT_LICENSE = LGPL-2.1
+DOVECOT_LICENSE = LGPL-2.1, MIT, Public Domain, BSD-3-Clause, Unicode-DFS-2015
 DOVECOT_LICENSE_FILES = COPYING COPYING.LGPL COPYING.MIT
 DOVECOT_DEPENDENCIES = \
 	host-pkgconf \