drm/i915/psr: Underrun on idle PSR wa only when pkgc latency > delayed vblank

drm/i915/psr: Underrun on idle PSR wa only when pkgc latency > delayed vblank

Underrun on idle PSR workaround (Wa_16025596647) is supposed to be
applied only when pkg c latency > delayed vblank. Currently we are
applying it always when other criterias are met.

Fix this by adding new boolean flag which is supposed to be set when
calculating watermark levels and pkgc latency > delayed vblank is
detected. currently this scenario is blocked but might be added
later. Due to this add also TODO comment into
skl_max_wm_level_for_vblank.

Bspec: 74151
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://lore.kernel.org/r/20250519075223.443266-1-jouni.hogander@intel.com