Revert "drm/i915: Use a dmi quirk to skip a broken SDVO TV output."

This reverts commit 6070a4a9.

The quirk for this SDVO device on IBM specific board is just a hack
in old code which showed the broken multifunction SDVO support in
the driver. Multifunction SDVO patch provided the right fix for it.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>