drm/i915/icl: Remove DDI IO power domain from PG3 power domains

The DDI-IO power wells (PWR_WELL_CTL_DDI) are backing
the IO/PHY functionality, which doesn't need the PG3
power power well. Accordingly fixing up the list of
PG3 power domains.

v2: Removed "DDI E/F IO"power domain as well [Imre]

Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190811081908.9114-1-anshuman.gupta@intel.com