drm/i915: Don't bail early from intel_dp_initial_fastset_check()

drm/i915: Don't bail early from intel_dp_initial_fastset_check()

Do all the checks in intel_dp_initial_fastset_check() instead
of bailing out on the first condition that triggers.

This makes for better debug logs since we see all the reasons
why the full modeset computation is forced.

Also avoid the risk of someone accidentally adding a check
later in the function that would require connectors_changed=true
(ie. no fastset at all), but an earlier check may have already
bailed out with just mode_changed=true (ie. fastset is still
possible).

Pimp the debugs with the encoder id+name while at it.

v2: Call the return variable 'fastset' to convey its meaning

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922191314.4252-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>