usb: cdns3: Added CDNS3_ID_PERIPHERAL and CDNS3_ID_HOST

Patch adds 2 definitions that make it easier to understand the code.

Reviewed-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>