atsam: Remove USB endpoint header (#6365)

The atsam USB hardware only requires that the ACM endpoint be endpoint
3.  As of commit 11828387 the atsam chips can therefore use the
default USB endpoints.

This will allow CAN bridge support for the SAME70 to function
(upstream host driver has hardcoded endpoints).

Signed-off-by: Alex Maclean <monkeh@monkeh.net>

src/atsam/usb_cdc_ep.h

@@ -1,10 +0,0 @@
-#ifndef __SAM3_USB_CDC_EP_H
-#define __SAM3_USB_CDC_EP_H
-
-enum {
-    USB_CDC_EP_ACM = 3,
-    USB_CDC_EP_BULK_OUT = 1,
-    USB_CDC_EP_BULK_IN = 2,
-};
-
-#endif // usb_cdc_ep.h