drm/i915: remove redundant if check

The extra check for connector_type is not required as we are already
checking for connector_type != DRM_MODE_CONNECTOR_DisplayPort.
The check was added by commit eb3394fa

 ("drm/i915: Add debugfs test
control files for Displayport compliance testing")

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>