OMAPDSS: HDMI: Correctly compare timings

There is currently a copy and paste error where the hdmi vsync timings are not
compared correctly, this patch fixes this.

Signed-off-by: Richard Röjfors <richard.rojfors@gmail.com>
[tomi.valkeinen@ti.com: fixed to apply on top of latest tree]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>