Update Policy PFW plugin makefile for PFW release 2.6.0

This patch updates the Policy PFW plugin with latest change within
PFW. It makes use of the dynamic xmlserializer library and does not
need anymore to link against xmlserializer library dependencies.

Change-Id: Ic7b912929a69d3906a34999c1ae25ddb9ac800e5
Signed-off-by: François Gaffie <francois.gaffie@intel.com>

Bug 246391