buildroot

tcf-agent: disable package for microblaze

For now, tcf-agent fails to build on microblaze. Disable microblaze
until upstream is fixed.

Fixes:

  http://autobuild.buildroot.net/results/72554c9c70c1a068e4ed6612e65ea294e678bb0c/

Signed-off-by: Norbert Lange <nolange79@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>