samsung:misc: set_board_info: set a proper $partitions at boot

samsung:misc: set_board_info: set a proper $partitions at boot

This change adds setting the environment variable: "partitions"
which is required to restore the partition table on the Trats2.

At this moment we are using MSDOS partition table on the Odroid
board, so for this board the above variable contains only a message.

Now the u-boot LCD menu in Trats2 is fully functional and the option:
(PWR+VOLUP) -> GPT restore - works well

Change-Id: Ia118179e98c3e3f4de209ce779e8cb3f81c09829
Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>