boards:sunxi: add Hyundai A7

Signed-off-by: Luc Verhaegen <libv@skynet.be>
boards:sunxi: add hbd mid s906 tablet

Signed-off-by: Luc Verhaegen <libv@skynet.be>
sunxi: fix up ordering and formatting in boards files

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