buildroot

libxml-parser-perl: add LICENSE_FILES

There is copyright information in the top level README file. Use this
file as the license file which will be included by the `legal-info`
build rule.

Signed-off-by: Ben Leinweber <bleinweber@spaceflight.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit 730da52edc45f2b72fc1d522ff184276d20c8b0d)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>