drm/imx: parallel-display: fix edid memory leak

The edid memory is only freed if the component.unbind() is called. This
is okay if the parallel-display was bound but if the bind() fails we
leak the memory.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
[p.zabel@pengutronix.de: rebased, dropped now empty unbind()]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>