package/cross-ldd: use Github download location

The crosstool-ng.org download link no longer works (probably a server
configuration of some sort), so let's switch to a Github
download. It's not an auto-generated tarball, but really the release
tarball, identical to the one on crosstool-ng.org, with the same hash.

Fixes:

  http://autobuild.buildroot.net/results/2ef16c821c4dcaaaa12b9b6c582da21a0592e453/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/cross-ldd/cross-ldd.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 CROSS_LDD_VERSION = 1.26.0
-CROSS_LDD_SITE = http://crosstool-ng.org/download/crosstool-ng
+CROSS_LDD_SITE = https://github.com/crosstool-ng/crosstool-ng/releases/download/crosstool-ng-$(CROSS_LDD_VERSION)
 CROSS_LDD_SOURCE = crosstool-ng-$(CROSS_LDD_VERSION).tar.xz
 CROSS_LDD_LICENSE = GPL-2.0
 CROSS_LDD_LICENSE_FILES = COPYING