fbdev: sh_mobile_lcdcfb: fixup LDHAJR :: HSYNPAJ needs mask

LDHAJR register will be broken by hsync_pos without this patch

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>