[PATCH/WIP] AT45DB011D flashing support

[Aidan Thornton]

Hi,

The attached patch is a somewhat messy attempt to add support for the
AT45DB011D and potentially other AT45DBxxxD Atmel DataFlash chips.
I've tested flashing the AT45DB011D-like integrated Flash on the
Xilinx XC3S50AN with it and it appears to work. Not really ready to
merge, but carldani asked me to post this so he could see if it could
be combined with his old incomplete code for non-power-of-2 flash
chips. Should in theory be able to read all AT45DBxxxD chips as-is and
write all chips that have 256/264-byte pages with suitable additions
to flashchips.c.

Aidan