drm/i915: Set the multiplier for SDVO on G33 platform

http://bugs.freedesktop.org/show_bug.cgi?id=21417



Signed-off-by: Sean Young <sean@mess.org>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>