drm/i915: Treat eDP as always connected, again

eDP should be treated as connected even if doesn't have an EDID. In that
case we'll use the timings from the VBT. That used to be the case until
commit f21a21983ef1 ("drm/i915: Splitting intel_dp_detect")
broke things by considering even eDP disconnected if we fail to get
an EDID for it.

Fix things up again by treating eDP as always connected.

Cc: Shubhangi Shrivastava <shubhangi.shrivastava@intel.com>
Cc: Nathan D Ciobanu <nathan.d.ciobanu@intel.com>
Cc: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Cc: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Cc: Larry Finger <larry.finger@lwfinger.net>
Reported-by: Larry Finger <larry.finger@lwfinger.net>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96675
Cc: drm-intel-fixes@lists.freedesktop.org
Fixes: f21a21983ef1 ("drm/i915: Splitting intel_dp_detect")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Larry Finger <larry.finger@lwfinger.net>
Link: http://patchwork.freedesktop.org/patch/msgid/1468836914-16537-1-git-send-email-ville.syrjala@linux.intel.com
(cherry picked from commit 1b7f2c8b0773d5ccbef43ef38a13ad33136c9679)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>