[ARM] S3C64XX: clock.c: fix typo in usb-host clock ctrlbit

The usb-host clock was using the wrong define (the SCLK enable for the
usb-host-bus) to change the HCLK register instead of the HCLK_UHOST bit.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>