drm/ingenic: ipu: Switch to drm_atomic_get_new_crtc_state()

drm/ingenic: ipu: Switch to drm_atomic_get_new_crtc_state()

The ingenic IPU atomic_set_property implementation uses the deprecated
drm_atomic_get_existing_crtc_state() helper.

This hook is called during the state building process, before
atomic_check, and thus before the states are swapped. The existing state
thus points to the new state, and we can use
drm_atomic_get_new_crtc_state() instead.

Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250930-drm-no-more-existing-state-v5-11-eeb9e1287907@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>