linux-mainline 3.8: add usb hotplug fix

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
contrib: bone-flash-tool: add emmc and mmc imaging scripts

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
contrib: bone-flash-tool: update emmc flasher script

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>