binutils: disable makeinfo

makeinfo is known to cause problems when building old texi files with more
recent host makeinfo.

In particular binutils-2.18 won't build on Fedora 20 without this change.

Even though more up to date binutils does build without this change there's
no guaranty it will with bump of host makeinfo in the future.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Anton Kolesov <akolesov@synopsys.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>