drm/i915: Stop using group access when progrmming icl combo phy TX

Program each TX lane individually so that we can start to use per-lane
drive settings.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211006204937.30774-8-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>