drm/sysfb: Do not page-align visible size of the framebuffer

drm/sysfb: Do not page-align visible size of the framebuffer

Only return the actually visible size of the system framebuffer in
drm_sysfb_get_visible_size_si(). Drivers use this size value for
reserving access to framebuffer memory. Increasing the value can
make later attempts to do so fail.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.16+
Link: https://patch.msgid.link/20260618084327.46567-2-tzimmermann@suse.de