drm/i915: remove Pineview EOS protection support

drm/i915: remove Pineview EOS protection support

HW guys have an evaluation about the impact about EOS, and say the impact
is quite small, so they have removed EOS detection support. This patch
removes EOS feature.

revert commit 043029655816ed4cfc2ed247020ef97e5d637392
directly reverting it gives a hunk error, so please use this one.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
[anholt: fixed up commit message for update that the feature's really gone]