To setup the default 'enable' setting the "dev_set_param(dev, "enable", "0");"
does not work as expected. After the call the parameter is still "<NULL>".
This is due to any change of the setting is rejected, if the same setting
is already active.
This patch also let the default setting be successfull, but only calls the
graphics backend if a change happens.
Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>