drm/i915/tgl: Re-enable rc6

We think that we got rc6 problems sorted out. Flip the switch
and let CI expose our tendency to naive optimism.
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190913200638.31939-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_pci.c

@@ -797,7 +797,6 @@ static const struct intel_device_info intel_tigerlake_12_info = {
 	.display.has_modular_fia = 1,
 	.engine_mask =
 		BIT(RCS0) | BIT(BCS0) | BIT(VECS0) | BIT(VCS0) | BIT(VCS2),
-	.has_rc6 = false, /* XXX disabled for debugging */
 	.has_logical_ring_preemption = false, /* XXX disabled for debugging */
 	.engine_mask = BIT(RCS0), /* XXX reduced for debugging */
 };