pixiewps: new package

pixiewps: new package

Pixie WPS is a C based tool to audit networks against so called "Pixie
Dust" attacks.

Signed-off-by: Guillaume W. Bres <guillaume.bressaix@gmail.com>
[Thomas:
 - fix license, it's GPL-3.0+
 - use PREFIX= instead of prefix= to actually have an effect, and
   install in /usr and not /usr/local
 - remove reference to PIXIEWPS_SUBDIR, which was never defined, and
   was not needed anyway]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>