Revert "bctoolbox: fix typos and logic error"

This reverts commit 5c4d3560.

Although the patch fixes the build error it does not set the flags for
Libs.private properly. A follow-up patch will provide a better solution
for this issue.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>