drm/i915/adlp: Fix AUX power well -> PHY mapping

On ADL_P the power well->PHY mapping doesn't follow the mapping on previous
platforms, fix this up.

While at it remove the redundant dev_priv param from
icl_tc_phy_aux_ch().

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210526143729.2563672-3-imre.deak@intel.com