Framebuffers in virtual memory are available via screen_buffer. Use
it instead of screen_base and avoid the type casting.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-5-tzimmermann@suse.de