drm/sysfb: Use new CRTC state in begin_fb_access

drm/sysfb: Use new CRTC state in begin_fb_access

Retrieve the CRTC's new state with drm_atomic_get_new_crtc_state()
in drm_sysfb_plane_helper_begin_fb_access(). The blit function might
be incorrect otherwise.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: cb71de092553 ("drm/sysfb: Lookup blit function during atomic check")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Closes: https://lore.kernel.org/dri-devel/aPJrs7_u8KcalNsC@intel.com/
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20251020125227.41308-1-tzimmermann@suse.de