drm/tilcdc: Convert to platform remove callback returning void

drm/tilcdc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

There is one error path in tilcdc_pdev_remove() that potentially could
yield a non-zero return code. In this case an error message describing
the failure is emitted now instead of

	remove callback returned a non-zero value. This will be ignored.

before. Otherwise there is no difference. Also note that currently
tilcdc_get_external_components() doesn't return negative values.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jyri Sarha <jyri.sarha@iki.fi>
Link: https://patchwork.freedesktop.org/patch/msgid/20231102165640.3307820-34-u.kleine-koenig@pengutronix.de
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Jyri Sarha <jyri.sarha@iki.fi>