toolchain: Fix glibc breakage

Introduced by previous patch 0f75b263,
this printf would break the build of glibc, because there is no format
to printf:

    printf: usage: printf [-v var] format [arguments]

Signed-off-by Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Reported-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>