ARM: atmel: add at91sam9g20ek_2mmc nand boot support

Add at91sam9g20_2mmc nand boot support. on this board, there is no
dataflash, so disable it

change one commet for at91sam9g20ek board

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
3 files changed