pylibtfdt: fix use of deprecated meson method

Fixes the following warning

> pylibfdt/meson.build:2: WARNING: Project targets '>=0.56.0' but uses
  feature deprecated since '0.55.0': ExternalProgram.path. use
  ExternalProgram.full_path() instead

Do not use full_path() as suggested. setup_py is being called as a
command by custom_target() which understands how to properly inherit the
object returned by find_program().

Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

pylibfdt/meson.build

@@ -1,5 +1,5 @@
 setup_py = find_program('../setup.py')
-setup_py = [setup_py.path(), '--quiet', '--top-builddir', meson.project_build_root()]
+setup_py = [setup_py, '--quiet', '--top-builddir', meson.project_build_root()]
 
 custom_target(
   'pylibfdt',