[U-Boot] [patch 0/1] fix hangup during boot when USB is used.

A recent commit (936897d4d1365452bbbdf8430db5e7769ef08d38) enabled the usb_stop() command in common/cmd_bootm.c which was not enabled for some time, because no board did actually set the CFG_CMD_USB flag. So, now the usb_stop() is executed before loading the linux kernel, which will result in a hangup during boot when USB has been started and stopped already (on AT91SAM).