igmpproxy: fix license

mrouted part of igmpproxy is licensed under BSD-3-Clause so add this in
IGMPPROXY_LICENSE and add hash for license files

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit c60c92861408d73e83fc819ac861f9fde962121c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/igmpproxy/igmpproxy.hash

@@ -1,2 +1,5 @@
 # Locally computed:
 sha256 e60331031f85d1fb834c5272a134f32d32e7834718da19ba3f787dff68389a31  igmpproxy-f47644d8fa7266a784f3ec7b251e7d318bc2f0a9.tar.gz
+sha256 be3d05af93dbbc4650f8d641d8e1bec220af4a729e07ba71e949c25b93a1b4f6  COPYING
+sha256 c4f65d5d396ad518a37d30b83fe33897661858dc174ff64a15d0461630ce64e4  GPL.txt
+sha256 4328a21f0822caa9976356623118bcdcc9970c7a0f9a3deeba23c779b7cfb5d1  Stanford.txt

package/igmpproxy/igmpproxy.mk

@@ -7,7 +7,7 @@
 IGMPPROXY_VERSION = f47644d8fa7266a784f3ec7b251e7d318bc2f0a9
 IGMPPROXY_SITE = $(call github,pali,igmpproxy,$(IGMPPROXY_VERSION))
 IGMPPROXY_AUTORECONF = YES
-IGMPPROXY_LICENSE = GPL-2.0+
-IGMPPROXY_LICENSE_FILES = COPYING
+IGMPPROXY_LICENSE = GPL-2.0+, BSD-3-Clause (mrouted)
+IGMPPROXY_LICENSE_FILES = COPYING GPL.txt Stanford.txt
 
 $(eval $(autotools-package))