drm/i915: mdelay(10) considered harmful

I missed this myself when reviewing

commit 237ed86c


Author: Sonika Jindal <sonika.jindal@intel.com>
Date:   Tue Sep 15 09:44:20 2015 +0530

    drm/i915: Check live status before reading edid

Long sleeps like this really shouldn't waste cpu cycles spinning.

Cc: Sonika Jindal <sonika.jindal@intel.com>
Cc: "Wang, Gary C" <gary.c.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449859455-32609-1-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Sonika Jindal <sonika.jindal@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 71a199ba

)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>