dwc2: support ISO transfer scheduling

Don't commit this, this is a proof of concept for now.

Author: Victor Brzeski

drivers/usb/common/usb_dwc2_hw.h

@@ -763,6 +763,7 @@ USB_DWC2_SET_FIELD_DEFINE(dctl_tstctl, DCTL_TSTCTL)
 #define USB_DWC2_DSTS_DEVLNSTS_MASK		(0x3UL << USB_DWC2_DSTS_DEVLNSTS_POS)
 #define USB_DWC2_DSTS_SOFFN_POS			8UL
 #define USB_DWC2_DSTS_SOFFN_MASK		(0x3FFFUL << USB_DWC2_DSTS_SOFFN_POS)
+#define USB_DWC2_DSTS_SOFFN_LIMIT		0x3FFFUL
 #define USB_DWC2_DSTS_ERRTICERR_POS		3UL
 #define USB_DWC2_DSTS_ERRTICERR			BIT(USB_DWC2_DSTS_ERRTICERR_POS)
 #define USB_DWC2_DSTS_ENUMSPD_POS		1UL