binutils: not available for the target on AArch64
Fixes:
http://autobuild.buildroot.org/results/74082860f607cbd857654e9504f5f7e7ae47c0ac/build-end.log
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>