board:sunxi: add t702a tablet

Signed-off-by: Luc Verhaegen <libv@skynet.be>
scripts: add script to check for duplicate sunxi dram files

Signed-off-by: Julian Calaby <julian.calaby@gmail.com>
scripts: add description to sunxi_dram_duplicates script

Signed-off-by: Luc Verhaegen <libv@skynet.be>