fbdev: remove tmiofb driver

With the TMIO MFD support removed, the framebuffer driver can be
removed as well.

Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Acked-by: Helge Deller <deller@gmx.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>