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