Also, use the border instead of border minus one.

At the same time, make sure the horizontal border and hsync are even for
the LVDS that works in dual-channel mode. So both horizontal border and hsync
start are also changed to be even, even for the LVDS in single-channel mode.

https://bugs.freedesktop.org/show_bug.cgi?id=20951Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>