Revert "drm/i915: Enable GMBUS for post-gen2 chipsets"

Revert "drm/i915: Enable GMBUS for post-gen2 chipsets"

Revert commit aa284bbef18145d40d97145f26bcd4732fd36292. This fixes a
hang when loading the eeprom driver (see bug #35572.) GMBUS will be
re-enabled later, differently.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Reported-by: Marek Otahal <markotahal@gmail.com>
Tested-by: Yermandu Patapitafious <yermandu.dev@gmail.com>
Tested-by: Andrew Lutomirski <luto@mit.edu>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>