omap-u-boot-utils: fix github tarball to use commit id

Signed-off-by: Spenser Gilliland <spenser@gillilanding.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/omap-u-boot-utils/omap-u-boot-utils.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 OMAP_U_BOOT_UTILS_VERSION = 8aff852
-OMAP_U_BOOT_UTILS_SITE = http://github.com/nmenon/omap-u-boot-utils/tarball/master
+OMAP_U_BOOT_UTILS_SITE = http://github.com/nmenon/omap-u-boot-utils/tarball/$(OMAP_U_BOOT_UTILS_VERSION)
 OMAP_U_BOOT_UTILS_LICENSE = GPLv2, GPLv2+
 OMAP_U_BOOT_UTILS_LICENSE_FILES = COPYING