package/libcanberra: fix LICENSE_FILES

The license file listed in the original commit adding the package in
a9ceaba794141e9f06d97aebc852b67b6fb501b8 did not exist.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libcanberra/libcanberra.mk

@@ -8,7 +8,7 @@ LIBCANBERRA_VERSION = 0.30
 LIBCANBERRA_SOURCE = libcanberra-$(LIBCANBERRA_VERSION).tar.xz
 LIBCANBERRA_SITE = http://0pointer.de/lennart/projects/libcanberra
 LIBCANBERRA_LICENSE = LGPL-2.1+
-LIBCANBERRA_LICENSE_FILES = LICENSE
+LIBCANBERRA_LICENSE_FILES = LGPL
 LIBCANBERRA_INSTALL_STAGING = YES
 
 LIBCANBERRA_DEPENDENCIES = host-pkgconf libtool libvorbis