Add extension udisk support

Manually Mount storage to host

#eMMC卡的major number跟minor number

# Write storage device path”/dev/block/vold/major:minor” in /lun?/file

echo /dev/block/vold/179:0 > /sys/devices/platform/fsl-usb2-udc/gadget/lun3/file

Manually unmount storage from host.
echo “” > /sys/devices/platform/fsl-usb2-udc/gadget/lun0

Automatic mount storage to host

#modify vold.fstab

http://markdingst.blogspot.com/2010_10_01_archive.html