drm/i915: add runtime PM support on Haswell

Now that all the infrastructure is in place and all the tests from
pm_pc8 pass, we can finally enable the feature.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1848,7 +1848,7 @@ struct drm_i915_file_private {
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
 #define HAS_PSR(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev))
 #define HAS_PC8(dev)		(IS_HASWELL(dev)) /* XXX HSW:ULX */
-#define HAS_RUNTIME_PM(dev)	false
+#define HAS_RUNTIME_PM(dev)	(IS_HASWELL(dev))
 
 #define INTEL_PCH_DEVICE_ID_MASK		0xff00
 #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00