build-artik: add helper utility to expand microsd
build-artik: add helper utility to expand microsd

After writing a prebuilt image into a sdcard, the sdcard will be
shrinked according to the prebuilt image size. To resize the
card, repartitioning and resizing is required.

sudo ./expand_rootfs.sh /dev/sd[X]

Change-Id: Ic8278fa43bb4ba7e7266bfdf954288c007a98f3a
Signed-off-by: Chanho Park <8ec285a53e21b773fd914e03c50e1b6431bc9aa8@samsung.com>

SamsungARTIK/build-artik