fbdev: sh_mobile_hdmi: add HDMI Control Register support

Latest SuperH HDMI uses not only HDMI Core Register (HTOP0)
but also HDMI Control Register (HTOP1).
This patch adds HDMI Control Register support.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>