fbdev: modedb: Add a new mode for 864x480 TAAL panels.

This adds a new entry to the modedb for 864x480 TAAL panels, the default
configuration for many OMAP boards. This enables omapfb to make use of
the standard mode parsing.

Signed-off-by: Mayuresh Janorkar <mayur@ti.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>