drm/i915: Extract intel_ddi_power_up_lanes()

drm/i915: Extract intel_ddi_power_up_lanes()

Reduce the copypasta by pulling the combo PHY lane
power up stuff into a helper. We'll have a third user soon.

Cc: stable@vger.kernel.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210128155948.13678-2-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
(cherry picked from commit 5cdf706fb91a6e4e6af799bb957c4d598e6a067b)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>