fastboot: Dynamic controller index for usb_gadget_handle_interrupts

Since we're now using a dynamic controller index for fastboot too,
usb_gadget_handle_interrupts should be using it instead of 0 (despite the fact
that it's currently not being used at all in the musb-new implementation).

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

common/cmd_fastboot.c

@@ -47,7 +47,7 @@ static int do_fastboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 			break;
 		if (ctrlc())
 			break;
-		usb_gadget_handle_interrupts(0);
+		usb_gadget_handle_interrupts(controller_index);
 	}
 
 	ret = CMD_RET_SUCCESS;