directfb: do not use inexistant configure options

The --disable-sysfs and --disable-explicit-deps options are not
supported by DirectFB anymore, so don't use them.

[Thomas: rework commit log.]

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>