usb_host: Rename struct/ll/hal files to use "usb_dwc" prefix

This commit updates the DWC_OTG based struct/ll/hal file names to
use the prefix "usb_dwc". This naming scheme reduces ambiguity if
another USB controller implementation is added.

As a result, "hcd.c" has been renamed to "hcd_dwc.c"

components/hal/include/hal/usb_dwc_hal.h

@@ -17,8 +17,8 @@ NOTE: Thread safety is the responsibility fo the HAL user. All USB Host HAL
 
 #include <stdlib.h>
 #include <stddef.h>
-#include "soc/usbh_struct.h"
-#include "hal/usbh_ll.h"
+#include "soc/usb_dwc_struct.h"
+#include "hal/usb_dwc_ll.h"
 #include "hal/usb_types_private.h"
 #include "hal/assert.h"
 

components/hal/include/hal/usb_dwc_ll.h

@@ -12,7 +12,7 @@ extern "C" {
 
 #include <stdint.h>
 #include <stdbool.h>
-#include "soc/usbh_struct.h"
+#include "soc/usb_dwc_struct.h"
 #include "hal/usb_types_private.h"
 #include "hal/misc.h"