drm/i915: Don't leak edid in intel_crt_detect_ddc()

In the path where intel_crt_detect_ddc() detects a CRT, if would return
true without freeing the edid.

Fixes: a2bd1f54

 ("drm/i915: check whether we actually received an edid in detect_ddc")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.6+
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484922525-6131-1-git-send-email-ander.conselvan.de.oliveira@intel.com