fwup: new package

fwup: new package

Signed-off-by: Wojciech Nizinski <niziak@spox.org>
[Thomas:
 - Add missing dependency on wchar
 - Rewrap Config.in help text
 - Add missing "depends on BR2_USE_MMU" on the comment about wchar
   dependency.
 - Switch to upstream 0.7.0 version
 - Replace the hook calling autogen.sh by a hook simply creating the m4
   directory, which is what prevented <pkg>_AUTORECONF from working.
 - Add patch to fix build with uClibc.
 - Split in separate patches the addition of the host variants of
   libarchive and libsodium.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>