linux-phytec-ti

fbdev: sh_mobile_hdmi: properly clean up modedb on monitor unplug

Even though this is not a problem currently, it is better to clear the freed
pointer and nullify the length of the freed memory.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>