drm/i915/psr: Add function for triggering "Frame Change" event

Add new function to trigger "Frame Change" event for ensuring we are waking
up before vblank evasion.

v2: dsb as a first parameter

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250213064804.2077127-12-jouni.hogander@intel.com