fbdev: sh_mobile_meram: Replace hardcoded register values with macros

Instead of hardcoding register values through the driver, define macros
for individual register bits using the register name and the bit name,
and use the macros.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

diff --cc drivers/video/sh_mobile_meram.c
Simple merge