drm/i915: Set active dpll early for icl+

To make the fastboot checks at least somewhat sensible let's mark
the expected DPLL as the active one right after we finished the
state computation. Otherwise intel_pipe_config_compare() will
always be comparing things against NULL/0.

TODO: This is still not really right. If the previous commit
had to fall back to the other PLL then the comparisong will
now fail. I guess intel_pipe_config_compare() should rather
be comparing port_dplls[] instead. But to do that we really
should just unify every platform to use the port_dplls[]
approach whether they have any need for PLL fallbacks or not.

Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907091057.11572-12-ville.syrjala@linux.intel.com