usb: dwc2: add defines to support s3c-hsotg driver

In preparation of combining the dwc2/s3c-hsotg driver in a single
DRD driver, the defines in dwc2/hw.h needs to get updated so that
the s3c-hsotg driver can use them.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
[ jh,rb - For gadget part only: ]
Tested-by: Jingoo Han <jg1.han@samsung.com>
Tested-by: Robert Baldyga <r.baldyga@samsung.com>
[ pz - Tested host part only. ]
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>