drm/i915/psr: Enable AUX-A IO power well on ICL for PSR

PSR requires AUX IO power well to be enabled. This was already in place
for CNL, extend this for ICL too. Not enabling the power well results in
the aux error interrupts when the hardware exits PSR.

Reported-by: Casey G Bowman <casey.g.bowman@intel.com>
Reported-by: Jyoti R Yadav <jyoti.r.yadav@intel.com>
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Cc: Jyoti R Yadav <jyoti.r.yadav@intel.com>
Cc: Casey G Bowman <casey.g.bowman@intel.com>
Tested-by: Casey G Bowman <casey.g.bowman@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180914001822.2503-1-dhinakaran.pandiyan@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -2077,7 +2077,7 @@ out:
 static inline enum intel_display_power_domain
 intel_ddi_main_link_aux_domain(struct intel_dp *intel_dp)
 {
-	/* CNL HW requires corresponding AUX IOs to be powered up for PSR with
+	/* CNL+ HW requires corresponding AUX IOs to be powered up for PSR with
 	 * DC states enabled at the same time, while for driver initiated AUX
 	 * transfers we need the same AUX IOs to be powered but with DC states
 	 * disabled. Accordingly use the AUX power domain here which leaves DC