drm/i915: Drop pipe A quirk for Thinkapd T60

The pipe A force quirk shouldn't needed except on 830. So let's nuke it
for the IBM Thinkpad T60 945 machines. This quirk pre-dates
KMS so it's usefulness is doubtful at best now.

The original bug report [1] describes the symptoms as "system hang on
closing T60 panel lid", and we already dropped a similar quirk for
another 945 machine in
commit 736a69ca ("drm/i915: Drop PIPE-A quirk for 945GSE HP Mini")
so I'm hopeful we can drop this one as well.

The quirk was added into xf86-video-intel in
commit 08903abe4dc0 ("Add pipe a force enable quirk for Lenovo T60")

[1] https://bugs.freedesktop.org/show_bug.cgi?id=16494



Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170601143619.27840-7-ville.syrjala@linux.intel.com


Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>