drm/i915/selftests: Add live vma selftest

drm/i915/selftests: Add live vma selftest

Add a live selftest to excercise rotated/remapped vmas. We simply
write through the rotated/remapped vma, and confirm that the data
appears in the right page when read through the normal vma.

Not sure what the fallout of making all rotated/remapped vmas
mappable/fenceable would be, hence I just hacked it in the test.

v2: Grab rpm reference (Chris)
    GEM_BUG_ON(view.type not as expected) (Chris)
    Allow CAN_FENCE for rotated/remapped vmas (Chris)
    Update intel_plane_uses_fence() to ask for a fence
    only for normal vmas on gen4+
v3: Deal with intel_wakeref_t
v4: Rebase

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190509122159.24376-4-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>