package infra: revert 0a4bd19f

Revert commit 0a4bd19f
Using --static is not documented and actually breaks static linking
according to my tests.
Fixes:
http://autobuild.buildroot.net/results/327/327c18db4e5d0ddc2c72a4684e103c19a1405e50/


...for external toolchains

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>