USB: ohci-s3c2410: use devm_ functions

The devm_ functions allocate memory that is released when a driver
detaches. This makes the code smaller and a bit simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>