git: use BR2_KERNEL_MIRROR as download site

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/git/git.mk

@@ -6,7 +6,7 @@
 
 GIT_VERSION = 2.13.0
 GIT_SOURCE = git-$(GIT_VERSION).tar.xz
-GIT_SITE = https://www.kernel.org/pub/software/scm/git
+GIT_SITE = $(BR2_KERNEL_MIRROR)/software/scm/git
 GIT_LICENSE = GPL-2.0, LGPL-2.1+
 GIT_LICENSE_FILES = COPYING LGPL-2.1
 GIT_DEPENDENCIES = zlib $(TARGET_NLS_DEPENDENCIES)