usb:hsotg:samsung: Remove platform dependency from s3c-hsotg

This code removes platform dependency from s3c-hsotg driver.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>