drm/i915: Only complain about n_edp_entries with eDP ports

commit 10afa0b6 ("drm/i915: Reject >9 ddi translation entried if port != A/E on SKL")
added sanity checks to make sure we don't end up with too many ddi translation
values for eDP ports, but it actually failed to check if the port is eDP.
We still look up the edp translations for non-eDP ports, but don't use
them, so we shouldn't be complaining about them either.

Fixes: 10afa0b6

 ("drm/i915: Reject >9 ddi translation entried if port != A/E on SKL")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452612496-9201-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>