package/opencv: disable toolchains affected by PR19405

opencv libphoto fail to link with the following error:
nios2-linux-gnu/bin/ld: BFD (Sourcery CodeBench Lite 2015.11-130) 2.25.51
assertion fail binutils-src-2015.11-130-nios2-linux-gnu-i686-pc-linux-gnu/bfd/elf32-nios2.c:1908

Fixes:
http://autobuild.buildroot.net/results/fd0cc1cb09d07be94770d984efb28eea7c6f25b7



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>