fbdev: sh_mobile_lcdcfb: Support multiple video modes in platform data

This is a preparation for HDMI hotplug support. This patch just moves all
platform defined video modes for the sh_mobile_lcdcfb driver to separate
arrays and switches all users to use element 0 of that array, so, this patch
doesn't introduce any functional changes and as such should not cause any
regressions.

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