at91 series: correct the smc bus width configuration

The flash connect on the boards are 8bits width, so correctly
configure them when do nand flash hardware init.

Signed-off-by: Bo Shen <voice.shen@gmail.com>
at91 series: remove dynamically configure nand flash bus width

when do board hardware init, we configure the nand flash bus width,
so no need to dynamically configure it again.

Signed-off-by: Bo Shen <voice.shen@gmail.com>
Merge pull request #8 from voiceshen/voice/remove_dynamic_config_nandflash_buswidth

Voice/remove dynamic config nandflash buswidth