drm/i915/wm: Extract skl_print_plane_ddb_changes()

drm/i915/wm: Extract skl_print_plane_ddb_changes()

We have skl_print_plane_wm_changes() but the DDB counterpart is
just inline in the main loop. Extract it into a function. We'll
have a second use for this soon.

The "ddb" part is already parametrized in anticipation of the
second user.

v2: Use prink field width for ddb_name alignment

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260319114034.7093-8-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>