video: sh_mobile_lcdcfb: Add wait for vsync.

Added FBIO_WAITFORVSYNC ioctl for SH-Mobile devices.
Tested on MS7724 and MigoR boards against 2.6.33-rc7.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>