drm/i915: No-Op enter/leave vt gem ioctl

We've killed ums support by now, it's time to reap the benefits. This
one here is getting in the way of doing some ring init cleanup.

Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

diff --cc drivers/gpu/drm/i915/i915_dma.c
Simple merge

diff --cc drivers/gpu/drm/i915/i915_drv.h
Simple merge

diff --cc drivers/gpu/drm/i915/i915_gem.c
Simple merge