drm/i915/skl: Enabling PSR on Skylake

Mainly taking care of some register offsets, otherwise things are similar to
hsw. Also, programming ddi aux to use hardcoded values for psr data select.

v2: introduce  EDP_PSR_AUX_BASE macro (Chris)
v3: Moving to HW tracking for SKL+ platforms, so activating source psr during
psr_enabling and then avoiding psr entries and exits for each frontbuffer
updates.
v4: Using SKL DDI AUX regs instead of changing PSR_AUX regs definition (Rodrigo)

Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[danvet: Drop the hunks to short-circuit sw tracking: We'd need to
push this down one level, and I don't fully trust the test coverage
yet to do so. So much prefer we pick a whitelist approach for the
cases we know work correctly.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7aee7d5..7add8cd 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2457,7 +2457,8 @@
 #define HAS_DDI(dev)		(INTEL_INFO(dev)->has_ddi)
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
 #define HAS_PSR(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev) || \
-				 IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
+				 IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev) || \
+				 IS_SKYLAKE(dev))
 #define HAS_RUNTIME_PM(dev)	(IS_GEN6(dev) || IS_HASWELL(dev) || \
 				 IS_BROADWELL(dev) || IS_VALLEYVIEW(dev))
 #define HAS_RC6(dev)		(INTEL_INFO(dev)->gen >= 6)