libpayload: Drop usb_fatal()

We have fatal(), which is just as good.

Coccinelle script:
  @@
  expression E;
  @@
  -usb_fatal(E)
  +fatal(E)

Change-Id: Iabecbcc7d068cc0f82687bf51d89c2626642cd86
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/395
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

payloads/libpayload/drivers/usb/usb.c

@@ -459,9 +459,3 @@ usb_attach_device(hci_t *controller, int hubaddress, int port, int speed)
 	return newdev;
 }
 
-void
-usb_fatal (const char *message)
-{
-	printf(message);
-	for (;;) ;
-}