mdadm: use BR2_KERNEL_MIRROR for SITE

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/mdadm/mdadm.mk

@@ -6,7 +6,7 @@
 
 MDADM_VERSION = 2.6.9
 MDADM_SOURCE = mdadm-$(MDADM_VERSION).tar.bz2
-MDADM_SITE = http://www.kernel.org/pub/linux/utils/raid/mdadm
+MDADM_SITE = $(BR2_KERNEL_MIRROR)/linux/utils/raid/mdadm
 
 MDADM_MAKE_OPT = \
 	CFLAGS="$(TARGET_CFLAGS)" CC="$(TARGET_CC)" -C $(MDADM_DIR) mdadm