compat_ioctl: move ATYFB_CLK handling to atyfb driver

These are two obscure ioctl commands, in a driver that only
has compatible commands, so just let the driver handle this
itself.

Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>