fbdev: sh_mobile_lcdcfb: fix bug in reconfig()

The function sh_mobile_fb_reconfig() contained a bug,
which caused the line_length to be set wrongly, if a mode
with a different X-resolution than the default one was chosen.
This caused 1080p24 mode to not work on AP4EVB.
Additionally the notifier chain was also called with the wrong
mode.

This patch fixes this, by using the X-resolution of the new
mode instead of the old one to calculate line length and
hands over the correct mode to the notifier chain.

Signed-off-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>