drm/i915/icl: Add missing combo PHY lane power setup

This step of the BSpec combo PHY port enabling is missing, so add it
now.

v2:
- Rebased on the new fixed v2 version of the helper.
v3:
- Use intel_ instead of icl_ prefix. (Jani)

Reported-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Madhav Chauhan <madhav.chauhan@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190425185253.3197-2-imre.deak@intel.com