[ARM] S3C: Rename S3C24XX_PA_USBHOST to S3C_PA_USBHOST

The USB host base address is available on both the S3C24XX and S3C64XX
ranges.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>