faifa: new package

faifa is a library and a cli used to manage PLC hardware that use
Intellon chipset.  Almost everybody use theses chips nowadays.

[Thomas: license is GPLv2+, not GPLv2. Fix indentation. Add dependency
on host-autoconf and a comment to explain what's going on. Fix
indentation of target/staging installation commands. Mark the package
as not available for static library builds as it always build a shared
library. Rewrap Config.in help text.]

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>