usb: dwc3: fix dwc3 header files

Changed the header files included in core.h and io.h to the u-boot header
files so that these files can be included in other dwc3 source files and
be compiled in uboot. Also added otg.h which has the defines for dr_mode.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
diff --git a/drivers/usb/dwc3/io.h b/drivers/usb/dwc3/io.h
index f9f22b0..b6da135 100644
--- a/drivers/usb/dwc3/io.h
+++ b/drivers/usb/dwc3/io.h
@@ -18,9 +18,7 @@
 #ifndef __DRIVERS_USB_DWC3_IO_H
 #define __DRIVERS_USB_DWC3_IO_H
 
-#include <linux/io.h>
-#include "debug.h"
-#include "core.h"
+#include <asm/io.h>
 
 static inline u32 dwc3_readl(void __iomem *base, u32 offset)
 {