ARM: S3C64XX: Add USB OTG HCLK to the list of clocks

Add the USB OTG HCLK clock to the list of clocks to be registered
during initialization.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>