fbdev: Select I/O-memory framebuffer ops for SBus

Framebuffer I/O on the Sparc Sbus requires read/write helpers for
I/O memory. Select FB_IOMEM_FOPS accordingly.

Reported-by: Nick Bowler <nbowler@draconx.ca>
Closes: https://lore.kernel.org/lkml/5bc21364-41da-a339-676e-5bb0f4faebfb@draconx.ca/


Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 8813e86f ("fbdev: Remove default file-I/O implementations")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.8+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240322083005.24269-1-tzimmermann@suse.de