xwm: move FILE to the callers of dump_property()

This is preparation for using the weston-debug infrastructure for
WM_DEBUG. dump_property() may be called from different debugging
contexts and often needs to be prefixed with more information.

An alternative to this patch would be to pass in the weston_debug_scope
as an argument to dump_property(), but then all callers would need to be
converted to weston-debug infra in a single commit.

Therefore require the callers to provide the FILE* to print to.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Maniraj Devadoss <Maniraj.Devadoss@in.bosch.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>