buildroot

support/test-pkg: move minimal.config into a separate file

This minimal configuration is also very useful outside test-pkg. In
addition, it will simplify the config merge in a later patch.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>